TEXT: DOCTOR WHO
  LOGOPOLIS
  Christopher H. Bidmead
  Based on the BBC television serial by Christopher H. Bidmead by arrangement
  with the British Broadcasting Corporation
  1.
  Events cast shadows before them, but the huger shadows creep over us
  unseen. When some great circumstance, hovering somewhere in the future, is
  a catastrophe of incalculable consequence, you may not see the signs in the
  small happenings that go before. The Doctor did, however - vaguely.
  While the Doctor paced back and forth in the TARDIS cloister room trying to
  make some sense of the tangle of troublesome thoughts that had followed him
  from Traken, in a completely different sector of the Universe, in a place
  called Earth, one such small foreshadowing was already beginning to unfold.
  It was a simple thing. A policeman leaned his bicycle against a police box,
  took a key from the breast pocket of his uniform jacket and unlocked the
  little telephone door to make a phone call.
  Police Constable Donald Seagrave was in a jovial mood. The sun was shining,
  the bicycle was performing perfectly since its overhaul last Saturday
  afternoon, and now that the water-main flooding in Burney Street was
  repaired he was on his way home for tea, if that was all right with the
  Super.
  It seemed to be a bad line. Seagrave could hear his Superintendent at the
  far end saying, 'Speak up . . . Who's that . . .?', but there was this
  whirring noise, and then a sort of chuffing and groaning . . .
  The baffled constable looked into the telephone, and then banged it on his
  helmet to try to improve the connection. If his attention hadn't been so
  
  engaged with the receiver he might have noticed a distinct wobble coming
  over the police box. Its blue surface shimmered momentarily and grew bluer.
  The whirring sound stopped, but then so did the voice at the other end as
  the line went dead. The constable looked ruefully at the telephone. Now he
  would have to cycle all the way back to the station and get permission from
  the Super personally, by which time the sun would doubtless be gone and
  with it the prospect of a relaxing afternoon in the garden potting out the
  sweet-peas . . .
  This speculation was the constable's last thought in this world. As he
  replaced the receiver his face was suddenly slammed up against the blue
  door, as if - but that was impossible - something inside the box had
  grabbed his hand.
  His arm disappeared up to the shoulder. His head lolled back, the eyes
  staring. As the throttled, terminal gasp bubbled away to a whisper in his
  throat, from inside the box echoed the light delicate sound of a chuckle.
  The TARDIS was full of surprises, but Adric wasn't ready for what he saw
  when he turned the corner.
  Suddenly he seemed to be in the open air, in a sort of crumbling stone
  courtyard, with a floor unevenly flagged with stone slabs. A few small
  twisted trees grew up between the flagstones, and beyond them the boy
  caught the crimson flash of the familiar flapping coat. At least he had
  found the Doctor.
  Adric was about to call to him when he was stopped by the solemnity with
  which the Doctor was pacing the pillared walk that flanked the quadrangle.
  His strange companion seemed deeply troubled.
  The Doctor must have sensed that he wasn't alone, because he slowed his
  steps and turned. So caught up in his thoughts was he that at first he
  appeared not to recognise the dark-haired boy. Then Adric found himself
  being beckoned across the quadrangle.
  The Doctor wasn't pleased to be disturbed; the cloister room was his
  special place for deep, private thinking. 'Whenever you see me in here
  pacing up and down like this, be a good chap and don't interrupt. Unless
  it's terribly urgent. It's not, is it?'
  The boy shook his head. The Doctor shook his too; it was as if there was a
  loose thought in there, rattling among the centuries of wisdom.
  'Well, now you know. In fact there's no need to come barging in here at
  all. If it's terribly urgent you can always ring the cloister bell.'
  Adric had never heard of the cloister bell. The Doctor explained that it
  was a sort of communications device. 'Reserved for wild catastrophes and
  sudden calls to man the battle stations.'
  'Battle stations? The TARDIS doesn't have them, surely?'
  'Not as such,' the Doctor replied vaguely. 'Still, I sometimes wonder
  whether I shouldn't be running a tighter ship.'
  He scratched at a nearby pillar. The stone was powdery, like chalk, and a
  rivulet of dust cascaded from the point beneath the Doctor's finger. 'I'm
  afraid the Second Law of Thermodynamics is taking its toll of the old
  thing.'
  The Alzarians had given Adric a Badge for Mathematical Excellence, although
  his grasp of physics wasn't very good - but on the journey from his home
  planet Adric had had plenty of time to learn from the Doctor, and now he
  knew about the Earth physicist Maxwell, and his ideas on entropy. Entropy
  was the waste energy that builds up in systems, the rust on the wheels, the
  weeds in the vegetable garden, the heat that eats away at components in the
  computer. Entropy seemed to be much on the Doctor's mind lately.
  Maxwell's Second Law of Thermodynamics consisted of two grim words:
  'Entropy increases.'
  The Doctor sighed. 'The more you put things together the more they keep
  falling to bits. That's the essence of the Second Law of Thermodynamics,
  
  and I never heard a truer word spoken. Have you seen the state of the time
  column lately? Wheezing like a grampus.'
  'It will get us to Gallifrey, won't it?' Adric asked anxiously.
  'Gallifrey?' The Doctor spoke the name of his own planet as if it were a
  new word in his vocabulary. 'Oh yes . . . Are you really set on visiting
  Gallifrey?'
  Adric nodded. 'That is where we're going, isn't it?'
  The Doctor sat down slowly. Luckily there was a carved stone bench set in
  the wall where they were standing, but there quite easily might not have
  been. 'That was the very question I was pondering, Adric. In a general way.
  There's bound to be a lot of fuss about Romana? Why she stayed behind in E-
  Space, official investigations, all that sort of thing . . . '
  'The Time Lords won't approve?'
  'As a Gallifreyan she's broken the cardinal rule - she's become involved,
  and in a pretty permanent sort of way. Perhaps we should let a few oceans
  go under the bridge before heading back home.'
  Adric smiled to conceal his disappointment. 'And see Gallifrey later?'
  The Doctor nodded, but in no very positive way. 'Let me put another idea to
  you . . . The place I have in mind isn't too far off our route. Well, sort
  of, give or take a parsec or two. It's my home from home.'
  He turned to Adric with a grin. 'You'll like it. It's that place called
  Earth I was telling you about.'
     
  That same afternoon, outside a cottage house in a quiet village-like street
  many hundreds of parsecs from where the Doctor and Adric were, but less
  than fifty miles away from all that remained of the unfortunate Constable
  Seagrave, a care-worn woman was sitting behind the steering wheel of a
  battered sports car that was almost old enough to have been new when she
  was a girl. Despite the spring sunshine, she was well wrapped up against
  the possibility of cold. There was, as she was fond of saying, no sense in
  taking chances with your health.
  A young woman in the neat purple uniform of an air stewardess came haring
  out of the house, her flight bag bumping at her side. 'Sorry to keep you
  waiting, Aunt Vanessa. Let's go.'
  Aunt Vanessa hadn't been having much luck with the starter. Each time the
  engine fired, then spluttered out.
  Tegan was barely twenty years old, but she was used to taking charge. 'More
  choke. And easy on the throttle as you turn her over.'
  Aunt Vanessa nodded her white fur hat towards the house. 'While I do that,
  dear, I wonder if you'd mind shutting the front door.'
  Tegan's Australian accent became even broader. 'Oh, rabbits! I promise I'll
  get organised one day . . . '
  Tegan closed the front door and ran back down the path again. 'Sorry, first
  flight nerves, I guess.' In obedience to her niece?s imperious gesture,
  Aunt Vanessa abandoned the intractable ignition switch and humped her
  bundled-up body across to the passenger seat.
  Immediately Tegan pulled the starter the old engine sprang to life.
  Clicking on her safety belt reminded her of the training course she had
  just completed, and she went into the routine. 'Good evening, passengers.
  To ensure continued safety on this flight it is necessary to draw your
  attention to the oxygen apparatus situated above each seating position . .
  . '
  Wary of draughts, Aunt Vanessa hunched further into her fur collar as the
  car pulled away from the curb.
  Tegan changed smoothly up into third. 'This is brought into operation by
  gently pulling the orange tag and placing the mouthpiece over the nose and
  mouth. Disposable paper bags, together with our flight magazine, may be
  found in the recess in the seat immediately in front of you . . . '
  And she drove off down the street. Although she didn't know it then,
  
  Tegan's route was destined to take her past the mysterious police box and
  onto a journey very different from the passenger flight her training had
  prepared her for ? a journey she would never forget for the rest of the
  life.
  Adric and the Doctor were walking quickly back through the maze of
  corridors to the TARDIS console room. It still puzzled Adric how the Doctor
  managed to find his way around the vast craft without a map.
  'Earth's the planet with all the oceans, isn't it?' Adric asked as the
  Doctor paused at a junction of three identical passages.
  'That's the chap.'
  'It sounds wet.'
  The Doctor set off again with long shambling steps that made it hard for
  Adric to keep up. 'Wet it is,' he said. 'At least, where we're going.'
  The Doctor had explained once already about the blue boxes, but it hadn't
  made much sense to Adric. A lot of what the Doctor said was like that.
  According to the Doctor the blue boxes looked more or less like the TARDIS,
  but weren't. They had no spacious accommodation, no viewer screens, and
  they didn't time-travel . . . Adric didn't see why the Earth people
  bothered having them.
  The corridor had petered out into a narrow passage. The Doctor stopped in
  front of a door. 'They're a sort of elementary communications device.
  Telephone boxes, from the Greek. 'Tele' meaning 'a long way', and 'phone'
  meaning 'sound', and 'box' meaning . . . ' The Doctor opened the door. It
  was a small cupboard. 'Meaning we're lost . . . '
  They weren't really, but the Doctor had to ask Adric not to ask any more
  questions while he concentrated on finding the way. It was quite some time
  before they were back in the console room, and the Doctor was able to
  resume a calm explanation of his idea about going to Earth.
  'I see,' said Adric. 'We're going to visit one of these boxes that are like
  the TARDIS.' It sounded to him like another of the Doctor's typically batty
  schemes.
  'You're getting your topsy mixed up with your turvy,' the Doctor corrected.
  'The TARDIS is very like it! The blue box is what the mathematical model of
  the TARDIS exterior is based on.'
  The Doctor was at the console, busily setting the co-ordinates for Earth.
  Even after several adventures with the Doctor there was so much Adric
  didn't understand about the Time Lord and his technology - but he wanted
  to, very much.
  'Block transfer computation,' the Doctor explained when he had finished at
  the console.
  A frown creased the smooth young face at his shoulder. 'I've never heard of
  that.'
  Adric's precocious seriousness amused the Doctor. 'No reason why you
  should. Logopolis is a quiet little place - keeps itself to itself.'
  'Logopolis? But I thought we were going to Earth.'
  'No, Logopolis is the other place. We take the measurements there
  afterward.'
  Adric was by now thoroughly confused. 'We're going to measure Logopolis?'
  'We measure the police box on Earth and then take the measurements to
  Logopolis...' said the Doctor patiently. Catching sight of the boy's blank
  expression he had the tact to add: 'I'm afraid I'm not explaining this very
  well. It's all to do with the problem of the chameleon circuit...'
  Adric opened his mouth, on the point of voicing another question. But at
  that moment the console room echoed to the sound of what might have been a
  big clock bell, deep-toned and stately. It seemed to be coming from a very
  long way away, and yet at the same time was somehow sinisterly present in
  the room.
  The Doctor stopped dead, as if rooted to the spot. The expression on the
  
  Time Lord's face sent a shiver up the boy's spine, and he froze too, and
  listened.
  It was the first but not the last time Adric was to hear the cloister bell.
  The traffic became heavier as they approached London, but Aunt Vanessa's
  little car was going splendidly. Tegan enjoyed the rush of wind in her hair
  and the feel of the engine under her control. She'd been a natural driver
  ever since the age of ten, when her father had first lifted her onto the
  springy steel saddle of the tractor on their sheep farm in Australia.
  Driving was great. But flying - that was really travelling. Tegan took her
  eyes off the road for a moment to glance up at the big blue canopy of the
  sky that seemed to go up and up without limit above them. Cars were all
  right, they got you moving, but they did keep you stuck on the one level,
  reminding you that you were just a little human being like everybody else
  with your feet in your shoes and your shoes on the ground.
  'Tegan! Look out!' Aunt Vanessa's voice broke abruptly into her
  meditations.
  The lorry was the size of a brontosaurus compared with Aunt Vanessa's
  little mouse of a sports car, and it was cutting in, straight across them,
  closing in from the middle lane. Tegan slammed on the brakes and wrenched
  the wheel over. The lorry passed in front of them with only inches to spare
  and travelled on towards London lumberingly unaware of the terror it had
  caused. With a screech of rubber the sports car thumped into the curb and
  came to a halt.
  'Oh, rabbits!' Tegan exclaimed, jumping out. Through the windscreen she saw
  Aunt Vanessa's face peeping out from its nest of white fur in dazed
  indignation. 'I'm sorry, Aunt, honestly. I'm usually a pretty good driver.'
  There wasn't any damage done to the body-work, but when Tegan saw the
  front nearside tyre her heart sank. 'Aunt Vanessa, it's a blow out.'
  The elderly bundle of fur extracted itself from the passenger seat to have
  a look. 'So it is. Dear me.' She was taking it quite sportingly,
  considering, Tegan thought. 'Well,' said Aunt Vanessa, 'what do we do now?'
  Unknown to them that question was already decided. Perhaps Fate is always
  lying in wait a few yards up the road; in this case for Tegan and her Aunt
  Vanessa it was already in view. If they hadn't both been hypnotised by the
  immediate but relatively trivial flat-tyre disaster that loomed so large in
  their minds, they could have spotted it from where they stood.
  It took the unusual shape of a blue police box. An abandoned bicycle was
  leaning against it, the small door that housed the telephone was open, and
  from it dangled the receiver on the end of its cord.
  Adric listened. Apart from the wheezing of the time column as it heaved up
  and down in the middle of the console, all was quiet. Adric found himself
  oddly disappointed. 'The cloister bell's stopped.'
  The Doctor nodded gravely.
  'What does it mean, Doctor?'
  'Nothing very much when it's not sounding.' The Doctor was trying to make a
  joke of it, but Adric could see that the Time Lord regarded the cloister
  bell as far from funny.
  'But something must have made it ring?'
  The Doctor bristled at the question. 'Not necessarily. It could well be our
  old friend entropy crumbling away at the systems circuitry. We'd better
  check the main logic junction.'
  With a quick glance at the console to make sure the flight to Earth was on
  track, the Doctor swept out of the console room. Adric followed.
  'Is that something to do with the chameleon circuit you were telling me
  about?' Adric asked.
  The Doctor said that it wasn't, and went on to explain that while he didn't
  
  mind being pestered with questions in the normal course of events - didn't
  mind at all, in fact found the boy's ceaseless interrogation of anything
  and everything rather stimulating - there were times (and this was one of
  them) when whys were unwise and silence was golden . . .
  They travelled down the corridors without saying another word, and the
  Doctor wrapped his own dark thoughts around himself, with faint sighs and
  mumbles escaping his lips from time to time.   
  Eventually they came to a large oval arch set into the wall of the
  corridor. It framed a kind of panel made of a translucent material that
  Adric discovered to be oddly heavy as he helped the Doctor lift it down.
  Behind the panel was what looked like a mass of fine grey hair, except that
  if you looked closely you could see that each hair had a tiny light that
  moved up and down its length. The effect was dazzling; the thing seemed to
  be alive.
  The Doctor poked the hair with his finger, and the lights flickered in
  response.
  'Nothing wrong with the main logic junction, then.' He signalled to Adric
  to help him put the panel back. 'Well, if the intermittent fault wasn't
  inside the TARDIS it must be outside the TARDIS. Someone must be trying to
  get in touch with us. Long way away, poor reception.'
  They began walking back the way they had come. The Doctor turned to Adric,
  as if seeking a second opinion. 'Don't you think?'
  'Why ask me?' There was a sulky note in Adric's voice. 'I don't know
  anything about it. And I won't know anything if you don't tell me.'
  The Doctor put his hand on the boy's shoulder. 'Sorry I snapped. I'm not
  quite myself at the moment. What do you want to know?'
  So as they made their way back to the console room the Doctor gave the boy
  a brief outline of the chameleon circuit, simplifying the maths to a few
  concurrent transcendental equations to convey the general picture. At least
  it explained how the inside of the TARDIS came to be bigger than the
  outside.
  The boy was quick to pick up the main point. 'So the inside space, where we
  are now, is non-existential?'
  'The dimensions are real enough, but they don't quite join up in the usual
  way.'
  'They couldn't, could they. Not if the exterior of the TARDIS only exists
  as a real space/time event and has to be mapped on to one of the interior
  continuums.'
  The Doctor nodded. 'Precisely. Very good.'
  'So you can turn it into anything you like?'
  'Ah? a very sore point. Yes - according to the handbook - the outer plasmic
  shell of the TARDIS is driven by the chameleon circuit.' But what the
  handbook said and what the TARDIS actually did were two rather different
  things, as the Doctor had long ago discovered.
  'In theory,' said the Doctor, 'the TARDIS can change its appearance more or
  less infinitely. In practice, however . . . '
  The Doctor's voice tailed off. He had come to a halt in front of one of the
  doors. 'I always meant to get Romana to help me fix it one day'
  The door was like all the others in the corridor. Rather oddly, almost as a
  ritual, the Doctor pushed it open. As Adric glimpsed the familiar
  furnishings, the soft curtains and the glass ornaments, he felt a pang for
  the absent occupant. She was at the Gateway with Biroc and the Tharils, and
  he had reconciled himself to the fact that there was no chance in the world
  of seeing her again. But he had completely forgotten about her room. That
  was a shock; it was as if part of her were still here after all.
  'I suppose we're going to miss her and K9,' said the Doctor in a voice that
  suggested the thought had only just struck him. He looked down at Adric,
  and the boy nodded, stuck for words.
  The Doctor took a deep breath. 'But . . . the future lies . . . '
  He looked up and down the corridor, pondering for a moment, as if not
  
  exactly sure which way the future did lie. Then he drew the door of
  Romana's room firmly shut and pointed to a branch of the corridor that ran
  off to the right.
  'This way,' said the Doctor.
  2.
  The time column was still oscillating uneasily when the Doctor and Adric
  got back to the console room. Silence seemed no longer to be golden for the
  Doctor; he was talking non-stop and Adric could hardly get a word in.
  ' . . . which would all be perfectly fine, except that the chameleon
  circuit's stuck. I first noticed it that time in the Totter's Yard, and
  that was many years ago. Come to think of it, there was probably something
  up with it even before that. She was in for repairs on Gallifrey at the
  very beginning of things . . . When I first . . . borrowed her.'
  'Borrowed her?' Adric was able to interject. Rather worryingly, the Doctor
  had vanished. Yet the voice continued . . .
  'On a sort of finder's keeper's basis. I should have waited until they
  fitted the new version of the chameleon circuit. But there were pressing
  reasons for my departure at the time.' His voice was coming from under the
  console unit. Adric walked round it to find the Doctor on his hand and
  knees working at something on the undersufface. 'Ah, that's got it . . . '
  
  said the Doctor.
  Adric jumped back as a panel rose vertically up out of the console under
  his nose, and then hinged forwards to form a horizontal table. The boy
  found himself looking down at a keyboard with numbers and letters.
  A lean Gallifreyan digit prodded a button on the console and the viewer
  screen opened. The full set of fingers danced briefly across the keys of
  the startling new keyboard, and soon the screen showed a shimmering blue
  outline picture Adric recognised.
  'The TARDIS exterior!'
  'Right. Now in theory, you should be able to do things like this . . . '
  The keyboard rattled as the Doctor entered in some more numbers and
  letters. While Adric watched, the picture on the screen slowly transformed
  into a solid triangular shape.
  'A tetrahedron,' said the boy knowingly.
  'Roughly, yes. Egyptian idea. A pyramid.' The Doctor worked at the keyboard
  again and an opening appeared in one of the sides of the object.
  Adric was doubtful. 'Yes, I suppose that's useful.'
  'Useful? A door's essential. We've got to be able to get in and out.'
  'No, I mean being able to change like that.'
  'Quintessential,' said the Doctor. 'Remember the Master.'
  It was the first time since they had left Traken that the Doctor had
  mentioned his deadly enemy by name. He said it lightly, with no special
  emphasis. But even so Adric shivered at this reminder of the evil renegade
  Time Lord who had plunged the home planet of his friend Nyssa into darkness
  and confusion.
  'If the chameleon circuit were working,' the Doctor mused, reaching for a
  lever on the console, 'I'd only have to pull this . . . and we'd be a
  pyramid.'
  The Doctor turned to Adric with a shrug. The picture on the screen had
  reverted to the police box shape. 'Can't get away from it, you see.'
  He seemed to need cheering up, so Adric said: 'But why do you want to? It's
  sort of distinctive. A friendly sight, to look at.'
  'And a sight too easy to look for. I'm not sure we should be distinctive.'
  Suddenly Adric understood the Doctor's concern about the chameleon circuit.
  The Master's own TARDIS had been in good repair, so he had been able to
  disguise it as something the Trakens thought was a harmless old statue. But
  the Doctor's vehicle was stuck in the shape of a blue police box - surely
  one of the most conspicuous objects in the universe.
  'It's not as if anybody's looking for us,' said Adric. 'You've disposed of
  the Master now. '
  'Yes . . . I did, didn't I?' the Doctor replied, with a certain unease that
  left an almost tangible silence hanging in the air for a moment or two. In
  his mind's eye Adric could still see the terrifying blaze of colour around
  the Keeper's Chair as the Master had met his fate.
  The Doctor cleared his throat. 'It may just be nonsense . . . but since we
  left Traken I've been feeling rather unsure about that . . . And then when
  the cloister bell rang . . . '
  The Doctor's eye fell on a small display screen set into the console, and
  in a blink of the eye he had thrown off the mood that had gripped him. He
  grinned at Adric. 'Ah, Earth,' exclaimed the Doctor, as if those dark
  thoughts were now a million miles away. 'Nearly there!'
  Aunt Vanessa looked down at the grass verge under her feet and worried
  about the rheumatic diseases that struck upwards from damp ground, even
  through sensible shoes and two pairs of stockings. Cars and lorries were
  whizzing along the by-pass not ten feet from where they stood, but none of
  them showed any signs of stopping to help. 'I really think we should
  telephone for help, dear.'
  Tegan shook her head. 'Feeble. We'll crack this ourselves, or not at all.'
  
  Her rummage in the boot had brought to light a greasy metal tube with a rod
  running through it at right-angles. 'Wheel spanner. Just the job.'
  Getting the hubcap off was easy. She jiggled the wheel spanner onto one of
  the nuts and stood on the lever. Eventually the nut came free, but as it
  turned it seemed to release a mysterious whirring, chuffing sound, which
  Tegan vaguely associated with the remaining air escaping from the tyre.
  Aunt Vanessa heard it too, coming from behind her. She looked round, but
  there was nothing there - only a couple of blue police boxes.
  'By the way, dear,' said Aunt Vanessa, not wanting to interfere, but it did
  look dangerous, 'don't you think we should put a jack under there before
  you take the wheel off? They always do it that way in the films.'
  Tegan straightened up. The dear old cinema-goer was perfectly right, of
  course. Tegan strode round to the boot again.
  Rabbits, rabbits, rabbits!
  The time column had stopped oscillating, and Adric knew this meant the
  TARDIS had come to the end of its journey. At a nod from the Doctor he
  worked the lever that opened the viewer screen.
  The shutters parted to reveal a broad expanse of some flat grey surface on
  which coloured objects streamed in both directions. Adric guessed it had
  been carved out of the countryside, because you could see the greenness and
  trees on either side. The coloured objects had wheels, and as you looked
  closer you could see they were primitive vehicles, with people inside.
  Close to them was a blue box, exactly like the TARDIS.
  'We've missed,' said the Doctor.
  'What's supposed to happen?' asked Adric.
  'I usually suppose we're going to miss.' The Doctor threw a disapproving
  glance at the console, and seemed to be addressing it directly. 'I just
  thought it might make a pleasant change to materialise on the right co-
  ordinates.' He checked some of the console settings, and made a quick
  calculation in his head. 'Two point six metres off target. What a landing!'
  'That's not bad,' Adric pointed out, in fairness to the old TARDIS.
  'That's what I said - what a landing!'
  Adric instinctively reached for the lever that worked the exit door, but
  the Doctor stopped him.
  'Aren't we going out there to measure it?'
  The Doctor shook his head. 'No need to draw attention to ourselves. The
  TARDIS and I are getting rather better at these short hops.'
  And the Doctor leaned over the console, gingerly resetting the co-
  ordinates.
  Aunt Vanessa and her niece had been too busy to notice the arrival of a
  second police box on the verge of the Barnet by-pass, so they certainly
  didn't notice its dematerialisation. Passers-by in their cars who were not
  too caught up in their own small immediate destinies might have seen -
  though nobody did - one of the big blue roadside objects shimmer into
  translucency and depart. By not seeing it, nobody was misled - for in fact
  the TARDIS did not depart.
  To be precise, what happened was this. At one moment there were two police
  boxes side by side. They seemed identical, though a close observer might
  have noticed that from one the telephone receiver dangled loosely on its
  cord, and the light on top of the other had begun to flash.
  And at the next moment there was only one police box. It was the one with
  the dangling cord, but the cord was no longer dangling. An Earth person
  watching from the verge would have found this very puzzling. But like a lot
  of problems the solution was simple from the inside.
  Adric was on the inside. 'You've materialised around it!' the boy
  exclaimed.
  
  The blue shape was swimming into focus inside the TARDIS console room: a
  police box with a dangling telephone.
  'With considerable finesse, as I hope you noticed.' The Doctor stepped
  forward to inspect it, something close to a smirk of satisfaction on his
  face.
  But the boy was worried. 'Are you sure it isn't another TARDIS, Doctor?'
  'I hope not. That would produce some very unpleasant dimensional anomalies.
  No, it's just an ordinary police box.'
  There was an official-looking notice on a small panel set into the door:
  Police Telephone Free for Use of Public. Advice and Assistance Obtainable
  Immediately. Officers and Cars Respond to Urgent Calls. Pull to Open.
  Adric had seen identical wording on the outside of the TARDIS, and had
  taken it to be some sort of joke of the Doctor's. Officers and Cars had
  never, to his knowledge, responded to Urgent Calls, although there were
  several occasions when he and the Doctor could have used a little extra
  help.
  He reached for the thing dangling on the end of a cord in order to tidy it
  away in the little box in the front door, but the Doctor quickly took it
  from him. 'Best not to touch,' the Doctor said. 'Heisenberg's Uncertainty
  Principle, and so forth.'
  'What's that?' the boy asked.
  'I'm not entirely certain. Something to do with not being able to measure
  an object without disturbing it.'
  The Doctor looked at the phone in his hand, and then waved it at Adric.
  'Disturbed it already, you see.' He paused to debate with himself for a
  moment whether to leave the phone as it was or hang up. Then he hung up the
  phone and delicately shut the little door.
  The Doctor seemed to know an awful lot of people with Rules and Theories
  and Principles. Adric opened his mouth to ask more about Mr Heisenberg, but
  the Time Lord shushed him with the gesture of a finger to his lips, and
  took a folding steel ruler from his pocket. 'Get something to write with
  and take these dimensions down,' said the Doctor. 'I've been meaning to do
  this for centuries.'
  The handle of the jack was so stiff that Aunt Vanessa had to help Tegan
  with it, which Tegan privately viewed as one small triumph in an afternoon
  of defeat. Together they managed to get the car propped up, then Tegan
  showed Aunt Vanessa how to work the wheel spanner, and went round to the
  boot again. She glanced at her watch as she hauled the spare tyre out. It
  was a good job they'd left Aunt Vanessa's house in plenty of time. There
  was no panic yet - as long as nothing else went wrong.
  'I'm so sorry,' said Aunt Vanessa, taking a very early rest from her
  efforts. 'What a thing to happen on your first day.'
  The wheel was caught up in the tangle of a string shopping bag and a dog
  lead and an old cardigan with holes in the elbows. 'Car's are OK,' said
  Tegan, 'but I guess I'm just spoiled with having our own plane back home.'
  It was a Cessna, and Tegan's father had taught her to fly, though he said
  she was still a little too impetuous to go solo.
  The moment Tegan dropped the tyre onto the verge she knew something was
  wrong. It wasn't heavy enough, and it didn't bounce with the sort of
  ringing sound you expect from a properly inflated tyre. She looked up
  accusingly at Aunt Vanessa. 'What kind of a maintenance schedule are you
  running here, Aunt V! This tyre's completely flat too!'
  Aunt Vanessa smiled a faint disarming smile that had always stood her in
  good stead when people from strange religious sects turned up on the
  doorstep. Tegan knew the smile of old, and refused to be warmed.
  She turned away and looked about her, as if seeking help from elsewhere. On
  the far side of the road, beyond the rushing traffic of all those people in
  cars who quite infuriatingly were getting where they wanted to go with no
  
  trouble at all, Tegan saw, standing on a mound of grass, a figure dressed
  in white, gazing in her direction. No, it wasn't white, it was a kind of
  gauzy, pale, vague, fading . . .
  Tegan blinked her eyes and looked again. There was nothing there. Or so she
  thought at the time.
  'There can't be much more of this,' said Adric, trying not to sound rude.
  His notebook was filling up with figures and the Doctor seemed to have been
  calling out measurements for ages.
  The Doctor was on his knees, and didn't look up. 'Measuring a police box
  means measuring it in every possible dimension.'
  Adric counted the entries in his note book. 'It can't have . . . thirty-
  seven dimensions. You said it was an ordinary Earth object.'
  'Every dimension and in every detail. The Logopolitans convert this into a
  precise mathematical model.'
  'Of the police box? Why?'
  'You're very fond of short words that begin with W and end in question
  marks,' said the Doctor, levering himself up to give Adric another
  measurement. 'I like to see that in the young. But by way of variation you
  might try longer questions like "What else can I do to help?"'
  'All right. What else can I do to help?'
  The Doctor pointed to the top of the police box. 'You can climb up there
  for me. Here, I'll give you a hand.'
  The top of the police box gave Adric a view of the console room he hadn't
  seen before, and it was odd to have the viewer screen below eye level. He
  noticed there were two Earth people working at a vehicle that had pulled up
  awkwardly onto the grass verge.
  Adric stared at the younger of the two women, feeling a strange tingle in
  his spine. It wasn't because her face looked rather beautiful, framed by
  that dark red hair under the severe purple cap that matched her uniform.
  Adric had the sudden completely ridiculous feeling that she was somebody he
  knew very well, though of course that was impossible, because he had never
  been to this planet before. Or perhaps it was the even more ridiculous
  feeling that he was going to know her!
  'Are you all right?' the Doctor asked, getting his attention by prodding
  him with the end of the folding ruler.
  Adric dismissed the thought from his head, but as the measuring continued
  he couldn't help casting occasional glances at the viewer screen.
  When at last the measurements were done they went over to the console to
  enter them into the memory management system. The Doctor seemed very
  pleased with the day's work, although Adric still wasn't sure why they had
  to go to Logopolis.
  'Didn't I explain that?' The Doctor seemed surprised. 'To overlay these
  dimensions on the TARDIS. The dimensional interference patterns will shake
  the thing loose.'
  Adric nodded slowly. 'And that's block transfer computation?'
  'Part of it. It's a way of modelling space/time events through pure
  calculation. It's not easy to explain in a word...'
  It took a lot of words. Adric gathered that over the centuries the
  Logopolitans had developed a completely new kind of mathematics that
  analysed the structure of the physical world - or rather the very nature of
  structure itself. But as the Doctor continued his explanation, with many
  diversions into astronomical history, wave theory, and even, at one point,
  the life cycle of the procyon lotor, it gradually dawned on the young
  Alzarian that the Doctor wasn't very sure of his ground theoretically.
  Block transfer computation! To Adric the idea of a mathematics that could,
  among other things, bring physical objects into being through pure
  calculation was immensely exciting. It was infuriating that a man who knew
  so much about completely useless things should be so woolly about such an
  
  important subject.
  The Doctor had begun his explanation while he was in the middle of
  resetting the co-ordinates. But in the course of talking to Adric and
  waving his arms about to illustrate points in his argument he had lost his
  place, and now he had to go back and start all over again. He would have
  finished the job with no trouble this time, if Adric hadn't asked, with a
  measure of deliberate irony, 'If it's all as easy as that, I don't see why
  we need to go to Logopolis at all. We can do it ourselves, here.'
  This brought the Doctor to a thoughtful halt. 'It's not that simple, of
  course . . . I went into it all when they first offered to do the chameleon
  conversion for me . . . it's highly specialised...'
  'A bit beyond our intellectual capability?' the boy asked innocently.
  'Well, I wouldn't say that. It's not just a matter of understanding
  distributed cluster algebra. The actual working out's very tedious, lots of
  fiddly computations. Much better to leave it to the Logopolitans. They can
  do it standing on their heads.'
  Adric was genuinely surprised. 'Not with a computer?'
  Doctor had encountered these idiomatic difficulties with Adric before. When
  you've been brought up in a different universe there are bound to be small
  cultural barriers, even with the best will in the world.
  'Standing on their heads . . . it's an expression.' The Doctor explained
  what it meant, and then went on: 'But now you come to mention it, they
  don't use computers. It's all done by word of mouth.'
  'Is that another expression?'
  The Doctor shook his head and muttered something. He was concentrating on
  the console, determined to get it right this time.
  'They speak it?' Adric exclaimed.
  The Doctor shrugged. 'Mutter. Intone.'
  'Intone the computations? Why?'
  'I wondered that too.' A mouthful of large white teeth beamed down
  disarmingly. 'Never quite had the nerve to ask them.' Then as he turned
  back to pull the dematerialisation lever the Doctor's eye was caught by one
  of the small indicator panels that were dotted about the console.
  There were so many knobs, levers, read-out displays and switches that Adric
  had, quite early on in his relationship with the Doctor, abandoned all hope
  of mastering the technology of flying the TARDIS, although he had managed
  to do it once, quite by accident. But the doctor knew exactly what he was
  doing, and silly, woolly or just plain baffling as he could be at other
  times, when working at the console he took life very seriously.
  So Adric knew straight away from the Doctor's expression that something was
  wrong.
  The Doctor tapped the indicator panel. 'You've got a lively enquiring mind,
  Adric. Explain this.'
  The panel was labelled Weak Force Flux Field Indicator, and the needle was
  jammed over to the right-hand side in an area marked in red as Beyond
  Limits.
  'It couldn't be an instrumentation fault, could it?' Adric suggested. The
  boy felt obliged to say something intelligent.
  'Very easily, knowing the state of the TARDI S.' The Doctor hit the panel
  again, this time with a certain amount of vindictiveness. On looking again
  he pumped his cheeks, making the breath whistle between his teeth. 'No, I
  don't think so. What we've got here is a gravity bubble. And fairly local,
  too.'
  'Is that dangerous?'
  'We'd better not dematerialise till we've investigated.' He threw Adric a
  less convincing replica of the reassuring grin. 'I'm probably overlooking
  the obvious again. Back in two shakes.'
  The Doctor jerked back a lever on the console and strode across to the
  double doors that swung open in response. Viewer screens and time
  technology were all very well, but nothing was better than seeing for
  
  yourself.
  The blue external doors opened a fraction. The Doctor peeped out and looked
  around.
  It was good to be back on Earth again. It was just the right size from the
  point of view of gravitational pull, and the atmosphere was rich in oxygen,
  which tended to give the foliage a green colour that was relaxing on the
  eyes. He stepped out and took a deep breath, forgetting for a moment that
  the TARDIS was parked beside the noise and the fumes of the passing
  traffic.
  Sunspot activity - he squinted up at the sky - seemed to be about normal
  for the time of century, but in any case the Doctor discounted natural
  causes: the field was too localised. There was no obvious high technology
  in the vicinity as far as he could see, and the landscape around him showed
  none of the secondary effects he would have expected, given the strength of
  the field. There would surely at least be a high wind.
  He remembered the turmoil of darkness that had blown across Traken at the
  time of the Keeper's passing, and how the Master had sought to step into
  his place. That last battle had certainly drained the Doctor's strength,
  but at least Traken had been restored to the harmony that had made it
  famous. Tremas the Councillor and his daughter Nyssa were happy again.
  What if the Master had somehow escaped from Traken?
  The Doctor pushed the thought out of his mind, and was about to duck back
  into the TARDIS again when his eye fastened on something on the far side of
  the road.
  A pale figure was watching, its outline humanoid in so far as it was
  definable. The Doctor stared, and the figure seemed to stare back. The
  Doctor reached out for support, and leaned against the TARDIS door, almost
  white-faced, his two hearts beating a little faster.
  Something quite extraordinary was happening. He had sensed it, and now -
  here it was!
  
  3.
  Inside the TARDIS the gravity bubble, or whatever it was, had produced a
  pearly cloud over the viewer screen. Adric wasn't particularly disappointed
  to have lost sight of the young woman who had given him such strange
  feelings, because the feelings had gone now, and he knew that the temporary
  giddiness must have been due to being so high up in the console room.
  In any case, there was something much more interesting to think about. In
  the Doctor's temporary absence, Adric's curiosity had drawn him towards the
  police box.
  The small hatch with the telephone in it wasn't the way in; it was only a
  sort of cupboard set in the main doors. And they were locked, just like the
  TARDIS. Adric took a metal coathanger from the hatstand and straightened
  out the hook so that he could work it into the lock to turn the tumblers.
  'Don't touch that!'
  Adric jumped at the sound of the Doctor's voice. 'Sorry, Doctor. I just
  thought it might have something to do with the gravity bubble.'
  The Doctor was grim-faced. 'I'm afraid you might be right. And that's a
  very good reason to leave it alone.'
  Adric stepped back from the police box. Then a small, extraordinary thing
  happened. One of the blue doors creaked slightly. As they watched it swung
  open as if of its own accord.
  The Doctor approached the police box cautiously, reached out for the second
  door handle, and began to turn it as if it were made of icing sugar and
  might break off at any moment.
  It was obvious straight away from the size of the interior that this was no
  ordinary police box. With tremendous care the Doctor stepped through the
  double doors.
  Perhaps it was the yellowish tinge to the light that made the room the
  Doctor entered so inhospitable: somehow sterile and dangerous territory.
  The air was cold, too, and as the Doctor looked about him the vapour from
  his breath hung in the atmosphere like puffs of smoke. Apart from this the
  Doctor felt at home, because it was home - or something very like it.
  'The TARDIS console room!'
  The Doctor heard the boy's exclamation without turning round. 'Get back to
  the TARDIS,' he hissed.
  'But this is the TARDIS, Doctor!'
  'A TARDIS, perhaps.'
  'It looks just like yours . . . '
  'Don't argue with me! Back to the console room and stay there.'
  The Doctor spoke with such force that Adric hastily bundled back into his
  head all the questions that were urging to be asked. He was about to move
  to the door when the Doctor reached out and grabbed him quite savagely by
  the shoulder.
  'Wait! Don't move. You may be safer with me.' The Doctor wasn't looking at
  Adric; his eyes were narrowed, fixed on some point on the other side of the
  console where the yellow light seemed particularly thick.
  The boy followed his gaze. The object was familiar enough, but for some
  reason the sight of it almost stopped his heart. Standing by the console of
  the room that was identical in every detail to the Doctor's console room,
  was a police box. Its small telephone door was open, and from it the
  receiver dangled on the cord.
  'It's hopeless, Aunt Vanessa! Just hopeless!'
  Tegan disconnected the foot-pump and threw it back into the boot. No amount
  of legwork would blow up a tyre with a hole in it. 'Honestly, Aunt Vanessa,
  how long have you been driving around with a dud spare tyre?' She looked at
  
  her watch, and the remains of her confident self-sufficiency evaporated
  into thin air.
  Aunt Vanessa remained cool. 'Don't worry, there's still plenty of time to
  get the garage.' She was peering across to the other side of the road; the
  point where it flattened away into the distance was marked by little
  fluttering flags enshrining what looked like a set of petrol pumps.
  Tegan stood the wheel on end. Her hands were smudged with grease and mud,
  but so far she had avoided getting any dirt on her uniform. She thought of
  the clean, air-conditioned interior of her 747; there was still time to
  catch the flight, if she made some quick, level-headed decisions. 'OK, Aunt
  Vanessa, I admit defeat. I won't be a jiff.'
  'Mind how you cross the road,' Aunt Vanessa called out after her, as Tegan
  set out for the garage, awkwardly rolling the tyre in front of her.
  That's a point, thought Tegan. How do I cross the road with this thing? But
  she had only gone a few yards when she came across the obvious solution to
  all their troubles. She read the notice. Police Telephone Free for Use of
  Public. Advice and Assistance Obtainable Immediately. Officers and Cars
  Respond to Urgent Calls.
  For some reason it said Pull to Open, which must have been a mistake.
  Because when she pushed against them the double doors opened inward.
  'That's funny,' said Tegan to herself, peering into the interior. 'That's
  very peculiar indeed . . . '
  And leaning the tyre against the outer wall, where she noticed somebody had
  been foolish enough to park an unlocked bicycle . . . Tegan stepped inside.
  The Doctor hung up the receiver and gently closed the small door.
  Adric shivered, and not just because of the cold. 'But if this is another
  TARDIS...!'
  'It may be, it may not be,' the Doctor interrupted. 'Too early to tell.
  Other things can produce this sort of dimensional anomaly.' Cautiously the
  Doctor pushed against the doors, but they seemed locked tight.
  Adric remembered that he was still holding the coathanger. At first the
  Doctor refused to let the boy approach the door himself and took the
  coathanger from him. But whatever else the Doctor was good at he certainly
  wasn't a natural lock-picker, and eventually he had to stand aside for his
  young companion. 'But please be very careful,' he warned.
  As Adric delicately explored the lock with the end of the wire the Doctor
  stayed close beside him.
  If Tegan had arrived in the real TARDIS console room a fraction earlier she
  would have seen the light on the roof of the police box spring into life,
  dancing blue reflections across the circular indentations that decorated
  the TARDIS walls. At the same moment the police box itself began to drain
  of colour and form; whirring and chuffing . . . it dematerialised like an
  idea forgotten.
  As it was, she entered through the double doors a split second too late,
  but the sight still made her catch her breath. 'It's some kind of . . .
  flying saucer!'
  She moved slowly towards the glitter of instrumentation in the middle of
  the room, frightened and yet drawn to the technology. It reminded her of
  the cockpit of the Cessna, as if the instrument panel of that small plane
  had been magically multiplied in the reflections of a kaleidoscope.
  She cast her eye around the walls, and noticed an old-fashioned hatstand -
  the last piece of furniture you would expect to see - complete with a few
  hats and a very long scarf that trailed down to the floor.
  At that moment the double doors of the TARDIS swung together and closed
  with a thud that resonated round the room. She ran to them, scrabbling at
  the unyielding surface for handles, anything to get them open. She was
  
  trapped!
  The yellow light thickened for each set of doors they went through, and
  each time the air was colder. The rooms were all the same in every other
  respect - it was what the Doctor called a 'simulacrum'. They always found
  the police box in the same place, a few feet to the right of the console as
  they entered through the doors. And each time the phone was dangling from
  its cord.
  Adric had suggested going back, but the Doctor had known it would be
  impossible. Adric didn't understand at first, and insisted on trying to
  leave the way they had come in. But the entrance was a heavy yellow
  nothingness when you approached it from the other direction; matter seemed
  just to cease.
  The Doctor's face was grim as he watched his young companion bring the
  coathanger to bear once again on the police box door. To Adric it always
  seemed to be the same lock. How many locks and doors? He had opened so many
  now that he had completely lost count.
  'It couldn't be an infinite regression, could it?' Adric asked through
  chattering teeth. The room they were entering was lit by even darker amber
  light than the last.
  The Doctor approached the police box and, as he had done so often before,
  picked up the receiver and hung up, closing the small door. 'There's a
  chance it may stop suddenly. Behind one of these doors there may be
  something completely different. Then we'll know it's over.'
  'And if we don't find something completely different?'
  The Doctor shrugged, but gave no other answer.
  'We'll be stuck here forever, won't we, Doctor? You can't get out of an
  infinite regression.' There was a note of panic in the boy's voice. 'That's
  true, isn't it?'
  'True, but boring,' said the Doctor. And with a wink to dispel any hint of
  tedium, he gestured to Adric to open the next police-box door.
  Tegan explored her prison. She was torn between immense curiosity about
  what was clearly some sort of flying machine, and a fear of the strange
  craft that was so unlike anything she had ever seen.
  She surveyed the array of switches, buttons and levers on the console.
  There must be intelligent life at the end of this lot, surely? One of the
  buttons looked rather like an intercom switch. She pressed it and spoke
  into the small grill beside it. 'Hello, anybody receiving me?'
  There was no answer. Collecting her courage, she tried some more buttons on
  the console. 'Hello? Come in, anybody . . . My name is Tegan Jovanka, and
  I'd like to talk to the pilot.'
  She stopped and listened. There was something. The sound came from behind a
  door she hadn't noticed before. She crossed over to it and pushed it open.
  Through it she glimpsed a corridor that appeared to lead deeper into the
  craft.
  She paused at the door and listened again. The deep note came in pulses,
  resonant like a bell. It sounded distant, but at the same time seemed to be
  very much an urgent presence in the room. 'Hello?' Tegan called into the
  corridor. 'Is that the crew through there?'
  There was no reply but the continued mournful chime. Tegan took a deep
  breath and walked through to explore the corridor. The punctured wheel, the
  airport and Aunt Vanessa were three minor problems that had slipped her
  mind completely.
  But Tegan was very much on Aunt Vanessa's mind. The elderly lady had been
  sitting wrapped up in the car for what seemed an age of waiting, and at
  
  last, being careful where she put her feet on the muddy verge, she had
  decided for the sake of her circulation to stretch her legs in the
  direction of the garage.
  The abandoned tyre leaning against the police box aroused her suspicions
  immediately. Something had happened to Tegan, and what was needed was a
  telephone.
  And there it was! Aunt Vanessa was so delighted to find Fate giving Luck a
  small push in her direction during the course of the afternoon's rigmarole
  that she forgot to be careful where she trod. She was within reach of the
  police box when her feet skidded from under her, toppling her against the
  double doors.
  They opened under the impact. When she scrambled painfully to her feet
  again she was standing on solid ground, astonished to find herself inside a
  large . . . laboratory, was it?
  She heard a light chuckle and turned round, still a little dazed from her
  fall. 'Tegan . . .? What on earth have you . . .! Goodness me . . . '
  The sight was so terrifying that before the threat had fully formed in her
  mind she was stumbling back towards the double doors. She struggled with
  them; they seemed to be closing on her, trapping her in with that . . .
  evil!
  And then her feet were skidding in mud again. She backed away from the
  monstrous presence that lurched towards her across the grass in slow-motion
  pursuit. Still it stayed with her, this chuckling thing for which she
  couldn't form a name, piercing her with a gaze that froze the thoughts in
  her brain.
  Somehow Aunt Vanessa found herself beside the tyre. She reached for it,
  hoping to use it for a shield, and despite its surprising weight managed to
  lift it from the ground. The chuckle that came from the pursuing figure was
  frankly derisive.
  The traffic on the road passed by unheeding. No one heard the throttled
  cry, the chuckle of triumph, or smelled the ozone left in the air by the
  sizzling discharge of the electronic device.
  Even the spare tyre that rolled out from the verge and wound its way
  between the stream of passing cars remained unnoticed for several minutes.
  The yellow light was so dense around them now that Adric could only make
  out the Doctor as a lumbering shape beside him. The boy's fingers were blue
  with cold and the locks were becoming harder to manage. With each door his
  heart sank deeper, and he could tell from the Doctor's voice that even a
  Time Lord's sense of proportion is not proof against all disasters.
  'Careful!' the Doctor whispered when the wire coathanger missed the lock
  and scraped across the face of the door that the dingy light had
  transformed from blue to a deep oily green. 'We're getting closer into the
  nucleus of the bubble . . . if it has a nucleus.'
  'It is a gravity bubble, then?'
  'With this many images there's only one thing it could be.'
  'What can be causing it, Doctor?'
  The Doctor hesitated, as if reluctant to share his thoughts with the boy.
  'When we materialised round the police box - someone had been here before
  us.'
  Someone? The lock was stiff, and as the Doctor's low whisper continued in
  his ear Adric had to concentrate to keep his mind on the position of the
  tumblers he could feel at the end of the wire. He understood what the
  Doctor was trying to say, but it was hardly thinkable. Another TARDIS,
  materialising round the police box before they arrived? Someone must have
  anticipated what he and the Doctor had planned to do!
  The lock clicked open. Adric turned his head towards the Doctor and his
  voice came huskily. 'But who?'
  The Doctor put his finger to his lips, and moving Adric gently to one side
  
  reached out to push open the door.
  The light of the sky rushed into their eyes. They were both astonished to
  find themselves in the open air, standing beside a police box on the by-
  pass.
  The police inspector had spotted the illegally parked sports car and
  instructed the constable to pull over. While the police inspector crossed
  the verge to investigate, the constable identified a hazard to traffic in
  the fast lane and nipped out between the passing cars with a due regard to
  safety to roll the tyre out of harm's way.
  The constable was gratified to see the inspector running towards him with a
  view to giving him a hand dragging the tyre onto the verge. Or so he
  thought, until the inspector reached him.
  What the inspector had to report was brief, breathless and, as far as the
  constable was concerned, utterly incomprehensible. The inspector was on the
  point of steering the constable over to the car to corroborate the story
  with the evidence of his own eyes, when they spotted the suspect.
  The constable knew at once from the gentlemen's attire that they'd got an
  odd one here. Your average member of the public does not wander abroad in a
  long red coat and even longer scarf.
  Despite the shock, from which he had clearly not properly recovered, the
  inspector was able to muster a professional tone as he addressed the
  tousel-haired newcomer. 'Good morning, sir. Would that be your vehicle over
  there?'
  The Doctor must have sensed unwanted complications. He signalled to Adric
  behind his back to stay under cover of the police box. 'Not mine,
  inspector,' said the Doctor, tactfully identifying the man's rank from the
  silver pips on his shoulder. 'No, I haven't driven for ages. Not a car,
  that is.'
  The inspector maintained a respectful tone, though his suspicions were
  hardening fast. 'I wonder how you come to be here, then. There's not much
  else here but the road.'
  'I . . . well, I admit that might be a little difficult to explain.'
  The Doctor found himself being steered by the elbow in the direction of the
  abandoned sports car. 'And while you're working that one out, sir, perhaps
  you could also have a go at explaining this.'
  The Doctor stared into the back seat, his face frozen into an expression of
  horror. What he saw confirmed his worse fears: somehow the Master must have
  escaped from Traken. When he spoke again the Doctor's voice was urgent.
  'He's still around here somewhere!'
  'He, sir?' The inspector glanced at the constable with a silent warning to
  be ready in case of trouble.
  'The Master, of course,' said the Doctor, pointing to the gruesome evidence
  in the back seat of the car.
  In the dreadful transformation every detail had been perfectly preserved.
  There was no mistaking the smart blue uniform of Constable Seagrave, who
  had last been heard of putting in a call down a bad line from the nearby
  police box.
  The other body was unknown to any of those present. But if Tegan had been
  there she would have been able to tell them that the inert shape, shrunken
  like the constable down to the size of a doll, was all that remained of her
  Aunt Vanessa.
  
  4.
  The Doctor was trying to explain something to the two official-looking men
  in blue uniforms. From behind the police box, Adric caught a few words:
  'Now just a minute, Officer. You don't realise what's going on here . . .'
  The inspector's face was a grey wall of officialdom. 'No, sir, but I'll
  take the details when we get back to the station. Lucky for you, it's not
  up to me to judge.'
  'Lucky? Oh, now surely you don't think . . .' The Doctor tailed off. He
  knew from past experience that jumping to conclusions was a favourite
  exercise on Earth. And people in uniforms were much the same all over the
  universe.
  The inspector glanced across at the constable. 'We're not paid to have
  opinions, sir. Just to do our duty.'
  'Well, I have opinions,' the Doctor retorted, gesturing towards the ghastly
  evidence in the back seat: 'This is the calling card of one of the most
  evil creatures in this universe, and I don't intend to stand here and
  debate the issue with you.'
  This last remark was as much for Adric's benefit as anything else. 'I'm
  afraid, gentlemen,' the Doctor went on, 'that I'm going to have to get
  after him.' So far the Doctor had been careful to avoid looking in the
  boy's direction. But now he threw the briefest glance towards the TARDIS,
  and momentarily caught Adric's eye. 'So, if you can help me create a
  diversion . . .'
  The inspector's eyebrows went up a notch further. 'Yes, I see, sir. You'd
  better come straight along with us.'
  'Of course, I'd love to. But . . .'
  With tact, but firmly, the constable took the Doctor's arm. 'To assist us
  with our enquiries.'
  
  Adric pressed back against the TARDIS, thinking furiously. Here was a
  chance to repay the Doctor for . . . well, for just being the Doctor. He
  remembered their first meeting on Alzarius, when the Time Lord and Romana
  had taken him in and tended his wounds, and how subsequently the Doctor
  hadn't minded all that much to discover the boy stowing away on the TARDIS.
  The two policemen began to steer their shambling suspect towards their
  car, and Adric had to back round a corner of the police box to stay out of
  sight. He didn't know that the thing he had stumbled over was called a
  bicycle, but it was portable, bulky and would provide a step up to the top
  of the TARDIS. It gave him an idea.
  The two policemen had a firm grip on the Doctor by the time they got to the
  car. When the constable stopped to open the door the Doctor allowed himself
  to be surprised by the sight of the police box, and said, as if the thought
  had just struck him, 'Would you mind awfully if I just phoned my
  solicitor?'
  'That's not for this sort of thing, sir. It's a police call box.'
  'That's what I like about this country!' The Doctor exclaimed, mustering up
  an authoritative enthusiasm that heightened the two officers' bafflement.
  'A place for everything and everything in its place!'
  Whatever the Doctor was planning to do next, he was obviously not about to
  get into the car willingly. The inspector had a way of dealing with
  difficult cases. 'If you're asking for a formal arrest, sir . . .' The
  inspector had already made up his mind that the tall tousle-headed man in
  the absurd red coat was dangerous, a lunatic perhaps. The big toothy grin
  he got from the Doctor in response to the official warning was further
  confirmation of this suspicion. In consequence the inspector was ready for
  anything - except the thing that actually happened. No reasonable person
  could have anticipated that a bicycle would come arching through the air
  above them, to land with a clatter on the police car roof. The Doctor was
  not a reasonable person in that sense, and in any case he had the advantage
  of glimpsing Adric the moment before, perched up on top of the police box
  with the bicycle held high over his head.
  When the two startled officers turned to their vehicle, the Doctor detached
  himself quickly from their company and sprinted towards the police box.
  'Quick! Get him, Davis!' The inspector's shouted command came too late. By
  then Adric had jumped down from the roof, almost tumbling onto the Doctor,
  and the pair of them had bundled in through the blue double doors.
  Constable Davis and the inspector squelched across the grass to the police
  box, to arrive there just as the lock snicked shut. The constable put his
  shoulder to the doors, and when they refused to budge he shouted and
  hammered on the panel with his fist, which gave the inspector a chance to
  demonstrate the superior intelligence that had earned him his rank.
  'No problem, Davis. He's in there, and we're out here. He can't stay cooped
  up forever.'
  'What do we do, sir? Sit it out?'
  'Can't waste the taxpayer's time, Davis. There's a key in the car. Get it.'
  Intelligence misleads. The inspector reasonably mistook the police box for
  a police box, but if he had known as much as the Doctor about the thing he
  was planning to unlock he would hardly have been so confident. Knowledge of
  that kind, however, would have involved certificates in time flow
  mechanics, not easily come by on Earth.
  The Doctor's own certificates were hanging on a wall in one of the TARDIS's
  rooms, although he couldn't remember which. That was the trouble with
  infinitely reconfigurable living quarters - to avoid confusion you tend to
  keep to a few favourite well-lived-in areas and leave the rest to the dust
  and silence. Certificates, in the Doctor's view, were historical evidence
  of having been taught something - not guarantees of present knowledge. They
  belonged in long-abandoned rooms.
  Even if they had been impressively decorating the console room walls, no
  amount of certificates would have told the Doctor why the TARDIS seemed at
  
  that critical moment to have forgotten all it knew about time flow
  mechanics, and was behaving as if it were nothing more than the inspector's
  plain and simple police box.
  It might have been the cloister bell. Adric had drawn the Doctor's
  attention to the sinister chime the moment they got through the doors.
  'It's ringing again, Doctor. Shouldn't we do something about it.'
  The Doctor was busy at the console. 'A choice of emergencies. In a moment.
  Better dematerialise first.'
  The police box - or whatever it was they had materialised around - was
  gone, and the Doctor very much hoped it had taken the gravity bubble with
  it. The console seemed to think otherwise. Adric knew little about the
  workings of the mechanism, but it wasn't hard to detect the laboured noise
  emanating from the time column, which flashed in a half-hearted way and
  resolutely failed to move.
  'It should be oscillating by now, Doctor.'
  The Doctor glanced down at the weak force indicator. The needle was lower
  now, but still well inside the red zone. 'The gravity bubble's still very
  close. It's dragging us back.'
  'What about the cloister bell?'
  'Shut the door.'
  Adric did so, but was uneasy about it. 'We can't just ignore it.'
  'Nonsense! Of course we can,' snapped the Doctor. Adric didn't know that
  the First Law of Crisis is to panic about one thing at a time. The Doctor
  was too busy with the console, checking the displays and making quick
  calculations in his head, to give lessons in the fundamentals. 'There must
  be something we can simplify here,' Adric heard him mutter to himself.
  Suddenly his bony index finger, which had been scanning the rows of dials
  and switches, descended on a small panel, stabbing at it accusingly.
  'Architectural configuration . . . that's the one!'
  Adric leaned closer to see what he was doing. The panel was labelled
  Interior Space Allocation, and at the touch of a few buttons was displaying
  what looked like a series of graphs with whole areas beneath the curves
  filled in with colour.
  Anticipating the question on Adric's lips, the Doctor said, 'We'll have to
  find some more power from somewhere. All this space,' he waved a loose hand
  at the panel, 'takes up energy. I'm going to jettison Romana's room.'
  'Are you sure?' asked Adric, very upset by the idea.
  Uncharacteristically the Doctor's temper flared up. 'Why do you expect me
  to be sure? This is life! Nothing is sure!' The boy couldn't remember ever
  seeing him so angry.
  The Doctor returned to the panel, and for a moment his finger wavered over
  the red button marked Execute. Adric held his breath. He knew the ominous
  tri-syllable only referred to the routine to jettison Romana's room, but
  from the tension in the air the word Execute might have applied to Romana
  herself. His mouth was dry. He felt he should say something to reassure the
  Doctor, but all that came out was, 'I'm sorry. I just wondered . . .'
  'This needs a quick decision, not a debate,' the Doctor snapped, as much to
  himself as to Adric. Then he pressed the button.
  Instantly the illumination in the console room flashed brighter. Adric
  breathed again, and the Doctor turned to him and nodded, as if some
  profound truth had been demonstrated. 'You see!' The time column began to
  wheeze into action. They had lost Romana's room, and regained access to the
  space/time vortex.
  The constable returned from the car and handed the key over to the
  inspector.
  On inserting it into the lock the two officers witnessed an unusual
  chuffing sound. Both raised their heads, mentally noting that the light on
  top of the box had begun to flash. The constable didn't think much about
  
  it, but the inspector voiced the speculation that it must be some sort of
  new security arrangement. He found it harder to explain what he saw next.
  The inspector pushed the doors open while the constable stood back, ready
  to help in the event of trouble. The first he knew of it was the expression
  on the face of his superior. The inspector turned to him and hissed:
  'There's some trick to this. Davis - I want a full report.' The constable
  followed the other's gaze towards the police box. His mouth slowly sank
  open, as if in silent mimicry of its compact empty interior.
  They were in flight. The oscillations of the flashing column that was the
  central feature of the console were regular now, riding the time waves like
  a ping-pong ball bobbing on the open sea. The Doctor was patching some
  hasty co-ordinates into the panel to fill the forward reference he had to
  file for take-off - Adric understood that much about programming the
  console - and some of the old liveliness had come back into his eyes.
  Adric was glad to be able to say something cheerful. 'We've done it,
  Doctor! That other thing - if it was a TARDIS - must have gone.'
  The Doctor turned from the console to face the boy: the light in his eyes
  had been a trick of the twinkling reflections from the panel lights.
  'Somehow I rather doubt it.'
  He cast a second look at the oscillating column, then, assured that all was
  well with the mechanism, took Adric by the arm and steered him towards the
  door that lead to the TARDIS interior.
  Adric found himself being ushered out into the corridor. 'What's the
  matter, Doctor?' the boy asked, confused. 'Aren't you going to answer the
  bell?'
  'This won't take a minute.'
  'What won't?'
  'Answering the bell,' said the Doctor as his head disappeared back into the
  console room.
  Adric blinked at the closed door. But before he had time to realise how
  hurt and puzzled he was by the Doctor's behaviour, the door opened again.
  The Doctor put something into his hand. 'Company while you're waiting. He's
  very strong on patience.' The door closed.
  The book was heavy, bound in dark-brown leather. Adric tipped it to look at
  the spine and saw it was called The Complete Poetry of John Milton. Opening
  the book brought a smell of distant classrooms. At the same time the
  corridor fell silent. The cloister bell had stopped tolling.
  Corridors! Tegan was sick of them. Whether you ran down them or walked,
  they all wound into more corridors, or branched into junctions that lead
  again to corridors, or perhaps opened out into halls, from whose tall
  archways sprang more junctions that narrowed inevitably to yet more
  corridors.
  Her state of mind had hardly been helped by the constant tolling, distant
  but always with her. And now, as she paused for breath, it seemed to be
  ringing in her head. She listened. It was in her head. Just in her head. It
  had stopped.
  She was lost - inside a crazy little blue phone box. And there was no one
  to help: just her, and the silence, and corridors from here to kingdom
  come. So when she turned a corner and saw the patch of daylight through a
  distant arch, she ran to it as a thirsty desert trekker might run to a
  water-hole.
  The daylight was a mirage; but she only came to that realisation after she
  had studied her surroundings for a long moment during which fear fought
  with curiosity, and both were slowly overcome by a rising indignation at
  the absurdity of the place. The ancient stone walls and the pillars
  supporting the arched roof of the walkway that circumscribed the courtyard,
  
  were all constructed inside a large dome. Some invisible source bathed this
  great roof with a pale blue light in emulation of the sky, even as far as
  the suggestion of clouds.
  She sat down on a low bench and said aloud, 'This place is completely and
  utterly daft.'
  As if in answer the stone columns around her trembled slightly to the
  reverberation of a faint whirring, chuffing sound. A patch of intense blue,
  attached to no particular object, seemed to be forming in the middle of the
  courtyard. Vague at first, it soon acquired corners and a flashing light on
  top.
  Tegan stood up slowly, staring in broad-minded Australian disbelief at the
  police box that had materialised in front of her eyes.
  The book was all printed in short lines that wasted a lot of the paper on
  the right-hand side of the page, and they gave the narrative a cumulating
  rhythm that Adric found unpleasant at first. But as he got into the story -
  it was about flying people called Angels who were at war against the Evil
  creatures that lived in a Burning Lake - the rhythm seemed to help the way
  the story built up.
  The Leader of the Burning-Lake Dwellers reminded Adric of the Master. Just
  as the Master had once been a Gallifreyan and was still a Time Lord, the
  evil character in the story was refugee Angel. So although the landscape of
  the story, with its Thunder and Lightning and Black Fire, was so obviously
  a fiction, this central correspondence with the truth riveted Adric's
  interest.
  He was ascending a huge staircase that lead to a gate built of gold and
  studded with diamonds when he was jolted back from the book to the
  normality of the TARDIS. The door was opening.
  The Doctor stood in the doorway, his face pale under the wild curls of his
  hair. 'Well, now we know,' was all he said as he ushered Adric back inside.
  'Know what?'
  'The message was very faint. But it was from Traken all right.'
  'Traken!' The bright angels flew from the boy's mind. 'How's Nyssa? What's
  wrong?'
  Taking time to choose his words carefully, the Doctor closed the door.
  Nyssa was safe enough; it was from her that the message had come. But
  Tremas, her father, had vanished. 'The Master must have had a second TARDIS
  hidden away somewhere,' the Doctor concluded. 'There's no doubt now that he
  escaped from Traken.'
  'And he's taken Tremas with him?'
  The Doctor made a vague gesture of affirmation; he had said as much as he
  dared tell the boy. Tremas, the brilliant Traken scientist and trusted
  Consul, had been a man in his prime, whereas the Master was very near the
  end of his twelfth regeneration. No Time Lord had survived the process for
  a thirteenth time. Clearly the Master had been desperate.
  Adric clutched at the Doctor's sleeve. 'Then where have they gone?'
  The Doctor hesitated. He couldn't tell Adric of his fears that the Master
  had physically taken over Tremas. Was he living in his body now? To achieve
  that was beyond the capacity of a Time Lord alone, but with some of the
  power of the Keepership still lingering . . .
  Angry with himself, the Doctor suddenly thumped the console. He had the
  self-control to choose a part some distance from the delicate array of
  needles, but the percussion was still enough to set them jumping. 'I was so
  sure we'd got him . . . But all the time he's been two moves ahead of me.
  He must have known I'd try to fix the chameleon circuit.'
  These were speculations he could share with the boy; indeed, he had to.
  After his escape from Traken the Master must have come to Earth to lie in
  wait, wrapping his own time machine invisibly around the police box. It was
  the only way to infiltrate his superior technology into the Doctor's
  
  TARDIS.
  There was one thing Adric didn't understand. 'But to know you were coming .
  . . he must have read your mind?'
  'He's a Time Lord too,' the Doctor brooded. 'In many ways we have the same
  mind.'
  Adric looked round the familiar walls of the console room and shuddered. If
  the Doctor was right the Master was somewhere in the TARDIS, imbedded like
  a virus in living flesh. If they landed in Logopolis they ran the risk of
  carrying the infection to an innocent planet.
  'Then we can't really land anywhere, can we?' the boy asked.
  Adric heard him mutter something in reply, but the Doctor wasn't really
  listening. His eye was wandering around the console room as if trying to
  trace the invisible string of a long tangled thought. The thought seemed to
  begin with the console itself and wind across the floor to the big double
  doors and then back again, eventually ascending slowly up the walls to the
  ceiling.
  The Doctor crossed to the small door that led to the TARDIS interior and
  pushed it shut, examining the way it fitted into the door jamb. He seemed
  satisfied by what he saw and went over to retrieve the TARDIS Manual from
  under one of the feet of the hatstand, where the small book spent a lot of
  its time compensating for an inadequacy in the hatstand design, or perhaps
  a slight unevenness of the floor.
  The Doctor had been leafing backwards and forwards through the pages for
  several minutes when he suddenly looked up brightly and said, 'Actually,
  there is one way of getting rid of him. I'm just trying to work out how
  much damage it might do to the TARDIS systems.'
  The Doctor explained his dangerous idea. In principle it should be possible
  to flush the Master out - literally - by the simple expedient of
  materialising the TARDIS under water and opening the doors.
  'Drown the TARDIS?' Adric exclaimed. 'But you can't!'
  'I can and I have to,' said the Doctor flatly. 'And that is that.'
  The strange pale blue light that seemed so like daylight must have been
  affecting her eyes, Tegan decided. The object she was examining was as
  solid as anyone could wish: a perfectly normal police box, even down to the
  stuff about police coming to your assistance written on the front. It was
  everything else that was crazy. She remembered - if her memory hadn't gone
  completely bananas along with everything else - that the crumbling stone
  courtyard she was in now, along with all that spaghetti of corridors, was
  supposed to be inside one of those police box things. Tegan was essentially
  a sensible girl, and she knew when she was out of her depth. What she had
  to do now was find some official person, preferably the captain of the
  craft - and give him a piece of her mind he would never forget.
  She had walked round to the back of the police box by now, just in case
  there was some trick to it. No, it looked, felt and smelled just like the
  real article. What she didn't see, as she leaned against the blue wall at
  the back trying to work out some positive plan of action, was the door at
  the front of the police box slowly edging open.
  
  5.
  He thought it was a map at first. And then as the details on the viewer
  screen grew larger Adric could see it was an aerial image of a real city.
  Traffic moved along the grey veins of roads between the buildings, many of
  which were stained with age, although patches of silver and glass
  highlighted some newer structures with gleams of sunlight. The main feature
  of the city was a thick grey-green river bangled with bridges. It lay
  across the centre of the screen like a serpent sprawled across a patterned
  cushion.
  The time column had stopped oscillating. They were hovering in mid-air.
  'London,' announced the Doctor.
  'Why not the sea?' asked Adric. 'You said there were a lot of oceans on
  this planet.'
  The Doctor crossed to the console and delicately re-set the co-ordinates.
  'It's an ancient tidal river called the Thames.' The watery burial of the
  TARDIS would be taking place somewhere worthy of respect, he assured Adric.
  'Besides, if we do it this way we won?t have so far to swim.'
  The boy helped the Doctor with the first part of the elaborate
  preparations. They had to close down most of the console system, and as the
  twinkling lights and little coloured instrument panels went out one by one
  the reality of what the Doctor was planning to do came home to Adric. A
  flood of water would sluice in and wash out the whole TARDIS. The console
  room, the corridors, the cloister room and the myriad rooms behind doors he
  had never opened would be drowned under tons of thick green water. It
  seemed such a drastic way of driving out the Master.
  'But you can't just abandon the TARDIS.'
  The Doctor passed an affectionate hand over the console. 'Yes, one does
  feel a tremendous loyalty to the old thing after all these years.'
  'I don't mean that, Doctor.' It seemed to Adric that the Time Lord was
  overlooking the obvious again. 'Be practical. How are you going to get to
  Logopolis?'
  The Doctor pulled a switch and the secondary lights at the base of the time
  column went out, leaving the console looking lifeless. The only working
  technology in the room now seemed to be the viewer screen, which still
  showed the serpent motif of the Thames. 'There's a gap in your education,
  Adric. Why are we going to Logopolis?'
  'To repair the TARDIS.'
  'And if we don't have a TARDIS?' The Doctor began to walk round the
  console, double-checking that all the switches were off.
  'But we've got to have a TARDIS! What are you going to do for transport?'
  'They also serve who only stand and wait,' said the Doctor simply, pointing
  to the works of John Milton that Adric was still holding, 'or haven't you
  got to that bit yet?'
  He approached the screen. 'We're partially materialised and hovering.
  There's just enough power in the peripheral reserves to keep us up until I
  short the lines with this lever. We'll drop the TARDIS . . . here.' He
  pointed to an area where the river widened.
  'Drop it?' The more Adric knew about the Doctor's plan the more dangerous
  it seemed. 'Couldn't we just materialise under water?'
  'This way we make sure we land in the right place. A gentle splash-down.'
  Nevertheless, the Doctor made sure of getting a good handhold on the
  console and persuaded Adric to do the same. 'Well . . . there may just be a
  slight jolt. Ready?'
  Adric nodded uneasily. 'Yes . . . if you are?'
  
  'That's not very affirmative,' replied the Doctor sourly. 'I'd feel more
  confident if you just said "yes".'
  They both held on tightly. The Doctor's hand closed on the lever.
  Leaning against the back of the police box, Tegan glowered around the silly
  courtyard with exasperation. In the absence of anybody to complain to or
  order about she had begun to talk to herself, addressing herself by name.
  'Right, Tegan. This is obviously some kind of elaborate joke, so we've got
  to find some way of putting a stop to it. The shock's the worst thing, and
  that's over. So everything's got to get better from here on in.'
  What happened next showed that her powers of prophesy were as
  underdeveloped as her geography, as far as the TARDIS was concerned.
  Although nothing of her surroundings changed in the few moments that
  followed, she experienced a sudden, deeply unpleasant sensation that made
  her heart pound. It was like being in a lift that has taken it into its
  head to make a violent downward lurch.
  She clung to the police box for support, feeling indignation and alarm, in
  that order. Then just as everything seemed stabilised again, a massive
  shock wave came up through the floor, cascading loose rubble from the stone
  walls and sending her flying.
  She picked herself up from the flagstones. 'This is just too much. It's
  unbelievable.' Apart from the dust her uniform was undamaged, although she
  could feel numb places on her body that were bound to turn into bruises.
  'Crazy idiot of a pilot. Wait till I have a word with him . . .'
  And then she froze. From the other side of the police box she heard a
  sound. If she had been convinced it was human she would have described it
  as laughter; a hollow, light chuckle.
  She remained still. Nothing happened. Without moving from the spot, Tegan
  called out cautiously, 'Who . . . who is that?'
  The same terrifying judder threw Adric up onto the console, and he came to
  rest against the stationary time column. Not until the reverberations had
  died down did he open his eyes. The first thing he saw was a sprawling heap
  of red coat, curls and scarf from which the odd arm and leg jutted out. The
  heap gathered itself together on the console room floor, and the Doctor's
  face grinned up at him.
  'Adric? Still with us?'
  The boy slid down from his perch and helped his companion to his feet. It
  wasn't his idea of a 'gentle splash-down' and he told the Doctor as much.
  The Doctor tried to make light of it. 'Must have touched the bottom.' When
  he had finished brushing himself down he noticed that the boy was still
  glowering at him in an unfriendly way. 'Look on the bright side, Adric. We
  were very lucky the water was there to break our fall.'
  Tegan's eyes darted around the cloisters, trying to detect among the stony
  shadows the figure whose presence she felt as a dank chill. The echo around
  the walkways made it impossible to locate the low chuckle precisely, but
  fear was urging her backwards towards the arch that had first brought her
  into the room.
  She touched the flaky masonry of the wall behind her, but what she had
  mistaken for an archway in the quick glance she had allowed herself turned
  out to be nothing more than a shallow alcove that rustled with ivy. Still
  not daring to take her eyes off the danger in front of her, she began to
  feel her way along the wall.
  The echo of that chilling sound floated through the walkway again, closer
  now. There was still nothing to see - or rather everything to see: darkly
  moving leaves among the foliage, deeper shadows within the shadows.
  
  The Doctor was standing with his back pressed hard against the doors, and
  his feet planted firmly on the TARDIS floor, as if getting ready to hold
  back a battalion of battering rams. Adric was by the console, manning the
  door lever.
  The Doctor went through it briefly once more, to make sure the boy
  understood. The trick was not to attempt to swim out while the water was
  rushing in. They would tread water and breathe while air remained in the
  console room; then when the influx had steadied they could pull themselves
  out through the double doors using hand-holds on the fittings. Until they
  got out into the open river attempts to swim were bound to end in being
  swept down by the current into the interior of the craft.
  'And be careful,' said the Doctor finally. 'The water pressure could send
  us both flying.'
  Then the Doctor gave the word. As soon as Adric had pulled the lever he ran
  over to the Doctor to help him with the doors, putting his back up against
  them and digging in his feet. Now that the security mechanism was released
  he had imagined it would take all his strength to hold back the flood,
  letting the water seep in slowly at first, just as the Doctor planned.
  In fact it was as easy as leaning against a wall.
  After a moment of getting the feel of the doors - this too was part of the
  Doctor's carefully developed plan - the boy looked at the Time Lord. The
  same question was in both their minds.
  'Perhaps,' said the Doctor slowly, 'we're not down very deep.'
  'Deep?' replied Adric. 'There's no pressure on these doors at all.'
  The Doctor paused, though he still didn't dare to let the doors go. 'I
  think you're right,' he said at last.
  'I am right.'
  'Very good, Adric. Very affirmative.'
  Together they straightened up and stepped into the middle of the room.
  There was no less stateliness than usual about the way the massive doors
  steadily opened inwards. And no torrent followed, not even a trickle.
  With an embarrassed glance at his young companion, the Doctor walked out of
  the TARDIS and found himself standing on a wooden floating pontoon moored
  by the river's edge.
  The pontoon had been eroded by the river and woodworm and time - mostly by
  time. It was a miracle the TARDIS hadn't gone straight through it. As it
  was, the planking had broken under the impact and the base of the TARDIS
  had been forced into it for a couple of feet, coming to rest against a
  metal girder that underpinned the wooden structure.
  The Doctor looked around the deserted riverside. On both banks abandoned
  dockland stretched as far as the eye could see, a landscape of rusty
  skeleton buildings wreathed in weeds. The water that rocked the pontoon
  from below was thick with greasy green algae. But for the motion it looked
  solid enough to walk on.
  'There you are, you see,' the Doctor said to the boy, who stepped out
  behind him. 'I knew there'd be a perfectly simple explanation.'
  Adric was glad of the Doctor's assurance that nothing serious had gone
  wrong with the plan. The initials TARDIS stood for Time And Relative
  Dimensions In Space machine, and it was a well-documented fault in the Type
  40 model that sometimes the time dimension was a little less relative to
  the other dimensions than it should be. According to the Doctor's diagnosis
  they had arrived at exactly the right spot - but a century or two too late.
  In the interim the bend in the river had silted up, moving the bank, and
  with it the pontoon.
  Although perfectly satisfactory as an explanation the Doctor seemed unhappy
  with it, as though the event were hedged about with other quite different -
  and perhaps unspeakable - possibilities. As the Doctor grew pensive, Adric
  became aware of the whistle of wind through the girders of a bridge that
  
  arched the river a little way upstream. The Doctor was staring at the
  bridge.
  'Well, we nearly got it right,' Adric said as cheerfully as he could.
  The Doctor stepped gingerly along the swaying pontoon for a better view of
  the bridge. 'Nearly - but not quite right,' he said absently. 'There's
  something not quite right about all of this. Before the police came, I saw
  something . . . somebody. Faintly, in the distance.'
  Adric's mouth was dry when he came to speak the name. 'The Master?'
  'The Master . . . perhaps that was it. Or perhaps . . .' The Doctor's voice
  tailed off into a chilling silence. His eye had come to rest on something
  high up on the bridge that overlooked them. Adric could swear the pale,
  vaguely defined figure hadn't been there the moment before. The distance
  made it quite impossible to distinguish any details of the face, but Adric
  knew positively that the solitary figure was looking directly at his
  companion.
  Eventually the Doctor said, in a strange harsh tone that was quite new to
  Adric, 'Nothing like this has ever happened before.' And without taking his
  eyes off the figure on the bridge, he gestured to Adric to stay by the
  TARDIS. 'I've got to get to the bottom of this,' was the Doctor's parting
  remark, as he left him to cross the broken pontoon towards the bank. He
  picked his way through the weeds and rubble, making for the bridge where
  the watching figure stood translucent against the sky.
  At first the figure didn't move, except to keep his face towards the
  Doctor, who was now scrambling over the rusty girders that littered the
  approach to the bridge. Then Adric saw the mysterious observer detach
  himself from his point of vigil and move towards the Doctor. Like a pair of
  duellists they met on the bridge, facing each other.
  The bargaining began; at least it seemed like bargaining from where Adric
  stood. The Doctor's scarf blew wildly in the wind, mimicking the earnest
  gesticulations of its owner. Whatever the Doctor was saying, the other's
  replies came more slowly and were less animated. But far from calming the
  Doctor down, they only seemed to be stirring him on to greater agitation.
  And then the Doctor was turning to gesture towards Adric, as if the boy's
  presence was somehow part of the debate. But whatever point the Doctor was
  trying to make, the other seemed obstinately to reject.
  Adric's fear crystallised into a single thought: the Doctor was face to
  face with somebody - or something - of which he too was terribly afraid.
  There had been no sound from the stone pillars or the police box for a long
  time now, only the rustle of the ivy she moved against in groping her way
  along the wall. But never for a moment did Tegan dare take her eyes off the
  courtyard in front of her: somewhere among those crumbling pillars, those
  small ragged trees, that invisible mocking presence must still be lurking.
  Then, close by her ear, came a sudden sharp bat-squeak, and a gust of air
  chilled her cheek. Tegan almost jumped out of her skin.
  It was a door, unoiled for centuries, moving in the breeze from somewhere
  outside. At last there was a way out! She rushed through it, slamming it
  shut behind her.
  She was back in the network of those endlessly winding corridors. Round and
  round, she thought, like a hamster in a cage.
  The Doctor marched into the console room, followed by Adric.
  'Door,' snapped the Doctor.
  Adric ran to work the lever, his head bristling with questions. But the
  Doctor was rapidly flicking switches on the console, bringing the colony of
  little lights and panels back to life. 'Co-ordinates. Come on, come on . .
  . Co-ordinates - are they set?'
  'Where are we going?'
  
  'Logopolis, of course. Set?'
  At a nod from his companion the Doctor pulled the dematerialisation lever
  and the time column began to flash and oscillate. At least everything was
  working; that was reassuring. But Adric found the Doctor's drastic changes
  of plan very unnerving, and so was the gloomy silence that settled over the
  console room once they were in flight . . .
  Adric's voice was small in the huge silence. 'Doctor? What . . . what
  happened out there?'
  'I have dipped into the future,' the Doctor replied, as if to himself. His
  face was a mask, animated only by the steady pumping light from the time
  column.
  The journey to Logopolis seemed to go on for ever. Eventually, when the
  Doctor detached himself from the console and began to pace the floor,
  walking in disconcerting unison with the oscillations of the time column,
  Adric could bear the tension no longer.
  'Aren't you going to tell me anything about it?'
  'Of course,' the Doctor replied, making a concerted effort to cheer up.
  'Well, as much as I can. Which isn't very much . . .'
  What it was that stopped him revealing everything he didn't say. Adric was
  able to deduce that the Doctor's concern with his own fate and that of the
  TARDIS was now almost a trivial matter. His fears were focused now on some
  future event or series of events that he was only able to describe
  obliquely.
  'On Earth they call it "bad luck". A chain of circumstances that seems to
  fragment the laws that hold the universe together. We're in for a run of
  it, a storm of it, a positive earthquake of "bad luck".' Then he took Adric
  by the shoulders and spoke to him face to face. 'The Master is a Time Lord
  - and that means we have an obligation to deal with him ourselves without
  endangering others.'
  'Keep it in the family,' Adric agreed. 'And we will.'
  'Not we, Adric. You are one of the others.'
  The boy flushed. 'But I can help you . . . can't I?'
  'In the ordinary way, yes, invaluable. But this is something far too
  dangerous.'
  A remark of the Doctor's had puzzled Adric. As a Time Lord he was always
  dipping into the future; that was precisely what had made the phrase so
  chilling. The answer was now written in the Doctor's eyes. He was talking
  about a kind of future normally closed to him - and that could only mean
  his own.
  'The man on the high bridge told you about the "bad luck"!'
  The Doctor nodded, and Adric drew a sharp breath. 'So it was the Master out
  there. You've done a deal with him!'
  The Doctor's eyes narrowed. 'How do you deduce that?'
  'I just guessed,' the boy said.
  'Never guess unless you have to. There's quite enough uncertainty in the
  world already.' And he didn't say another word until it was time to land in
  Logopolis.
  The Doctor deemed it polite to show himself first, by way of warning the
  Logopolitans of his arrival. He put the TARDIS into hover mode above the
  City and flicked on the viewer screen.
  The two travellers looked down on a huge shallow dome smoothed out of the
  pale rose natural rock. Swirling involutions etched deep into its surface:
  these seemed to be the city streets, for in the depths of the pink shadows
  Adric could just make out cave-like holes that he took to be dwelling-
  places. Apart from a few tiny moving figures there was little sign of life.
  From the perspective of the hovering TARDIS the City of Logopolis looked
  like a giant brain.
  At one end the rock piled up into a mound that might have been a single
  
  large building - some kind of scientific establishment, Adric deduced from
  the massive parabolic antenna mounted above it. A transmission site,
  perhaps?
  The Doctor approached the screen and looked hard at the big skeletal bowl
  of the aerial, unable to answer Adric's question. 'Must be a recent
  addition. There'll be plenty of time to find out all about it.'
  He touched a button on the console and the TARDIS began to move across the
  City to where the smooth dome of rock graduated into a flat plateau. Then,
  as they prepared to land the most extraordinary thing happened.
  The door leading to the inner part of the TARDIS opened with a bang. Tear-
  stained, showing signs of her exhausting wanderings through the maze of the
  TARDIS corridors, the red-haired girl in the purple uniform marched into
  the room.
  Tegan's voice exploded like a shrapnel-bomb in the quiet of the console
  room. 'I demand to see whoever is in charge of this ship.'
  6.
  The plateau at the north end of the City was flat and open, overlooking a
  horizon of pale rose sands that merged mistily into the opalescent sky. But
  the silent figures in flowing dark robes had not gathered in the High Place
  to look across that breathtaking view. As more of their number spilled in
  from the direction of the City, stepping out from the shallow gullies which
  in their southward development became the myriad alleys of dwelling places,
  all eyes were turned towards the materialising blue police box.
  Their Leader was a man of about sixty, though from his assured posture and
  the shine of his skin beneath his short steel-grey hair he seemed to be in
  his prime. The crowd around the TARDIS thickened and the Leader stepped
  forward to greet the Doctor.
  But rather rudely in the face of all this hospitality the TARDIS door
  remained closed.
  Tegan was the cause of the trouble. She stood defiantly in front of the
  console, facing the Doctor and Adric.
  'I've told you - Tegan Jovanka. It's my name. And before I answer any more
  questions, I want to know exactly who you are.'
  Adric briskly introduced himself and the Doctor.
  'And this,' said the Doctor, pointing at the viewer screen which now
  displayed the sombrely dressed crowd gathering around the TARDIS, 'is
  Logopolis. Where I happen to have some urgent business. What am I going to
  do with you?'
  Tegan had a very positive answer. 'You can take me right back where you
  found me. My aunt is waiting in her car to take me to the airport.'
  
  The Doctor had just taken the data block out of the memory management
  system and was on the point of reaching for the door lever. 'Your aunt? A
  plump brown-haired woman? A red sports car?'
  Tegan was taken aback. 'You know Aunt Vanessa?'
  'I've . . . er . . . seen very little of her,' the Doctor prevaricated.
  'Right, that settles it. You'll have to come with us.' He levered open the
  door, waving Adric and Tegan out towards the waiting Logopolitans.
  At that moment there was no blue police box inside the cloister room. A
  handsome dark green tree of the variety Prunus Laurocerasus, or cherry
  laurel, had, however, become apparently firmly rooted in the ground a
  little distance from where the Doctor, Adric and Tegan emerged to face the
  welcoming party. The Master's TARDIS did not suffer from the same defects
  as the Doctor's. In particular, the chameleon circuit was working
  perfectly.
  The Doctor allowed the Leader of the Logopolitans to conclude his short
  speech of welcome. Crisp, well-regimented applause illustrated that
  Logopolis was indeed honoured by the Doctor's visit.
  'Nice of you to put it like that, Monitor,' said the Doctor. 'I arrive . .
  .' he threw a meaningful look towards Tegan ' . . . with a somewhat
  enlarged entourage. But we're very honoured to be here.'
  Tegan was about to raise her voice in protest, but Adric lifted his finger
  authoritatively to his lips, a trick the Doctor often used.
  The Doctor and the Monitor began to saunter towards the pink folds of rock
  that led to the City. Promising to explain everything if she promised in
  turn not to make a fuss in front of all these important people, Adric
  induced Tegan to follow.
  'Time has changed little for either of us, Doctor,' the Monitor observed.
  'You continue to roam the universe, and we persist in our simple existence
  on this planet.'
  The Doctor laughed. 'That antenna on the other side of the city - far from
  simple, I should have said.'
  'Occasionally our researches require what is sometimes called
  "technology".' With a generous sweep of his hand the Monitor acknowledged
  the Doctor's point. 'But for the most part our computations are enough.'
  The gully they were walking along had grown into a small, smooth-shouldered
  canyon. Logopolis began here. Adric detached himself from Tegan's whispered
  questions long enough to look closely at the caves he had noticed from the
  TARDIS; he now saw they were square, open-fronted cells carved from the
  rock on either hand. At first they dotted the walls intermittently, but as
  the Doctor's entourage drew closer to the heart of the City the
  perforations became more regular, until eventually they were completely
  adjacent, with only a column width separating each cell, row upon row of
  them, winding the full distance of every street.
  The crowd, that had been following at a respectful distance, was now
  diminishing. One by one the Logopolitans left the procession, each taking
  up his station at the entrance of his small, well-ordered dwelling.
  The air had begun to chirrup to a sound that might have come from a swarm
  of large crickets. The Doctor was so deeply engaged in his philosophical
  exchange with his distinguished host that he seemed not to hear it. Adric
  couldn't explain it to Tegan - there was a lot that he hadn't been able to
  explain - but at that moment they turned a corner that looked down into a
  street they had already passed.
  A Logopolitan sat at the entrance to each cell working beads on a kind of
  small frame held on his lap. 'They're just like abacuses!' Tegan exclaimed.
  As he clicked his beads each seemed to be chanting softly under his breath,
  and Adric remembered what the Doctor had said about the muttering and
  
  intonation. Waves of information were being passed from cell to cell,
  calculated upon and then passed on again to the next. It was like being in
  the middle of a huge, living calculating machine.
  The canyons became tall. The Monitor lead them towards a building that was
  far larger than the rest, boasting what appeared from the layout of the
  windows to be several storeys. They mounted the flight of steps that lead
  to the big rectangular entrance.
  What was left of the crowd remained outside. Tegan was thankful at least to
  find the air cooler in the large hall. And then there were more of the same
  pink steps, before they entered a room that was quite different from the
  other architecture she had seen. Its surfaces were perfectly even and
  rectangular, certainly not carved from the rock.
  'Our Central Register,' the Monitor announced.
  'You have been busy, Monitor,' said the Doctor, handing over the data
  block. 'All this is new.'
  'And more than we need for our immediate researches. Back-up facilities.'
  The Monitor took the data block over to a long grey work-station that ran
  the entire length of the wall and settled himself in front of what looked
  at first like a black console screen. Adric expected some picture to appear
  there when the Monitor put the data block in front of it. But instead the
  Logopolitan leaned forward and, consulting the data block from time to
  time, began to whisper. Adric edged closer and saw that what he had taken
  to be a screen was a dark cavity in the wall.
  The sound was meaningless to Adric. It was composed of short words that the
  Monitor articulated with great clarity, carefully separating each from the
  next as though every syllable were precious. Somehow Adric was reminded of
  the words in the story about the Angel. But the rhythm in the Monitor's
  incantation owed much to the fact that the same sounds kept coming round
  again and again.
  'Kayrie gorrock gorrock kayrie zel. Kayrie nerus nerus kayrie zel. Kayrie
  av kayrie av perdunesta zel. Ressa carra otto perdunesta zel . . .'
  Out in the narrow streets the susurration of sound was changing, taking on
  the shifting rhythms of the Monitor's voice as the new whispered numbers
  chained from cell to cell. The abacuses began to clack their calculations,
  building to a fugue that echoed through street after winding street.
  At the very edge of Logopolis the sound of the whole city blended into the
  moan of the wind hurrying over the plateau from the stretch of rosy sands
  below. Two objects dominated the high flat ground: the TARDIS and a plump,
  cherry laurel tree, whose dark-green, glossy foliage marked it as an
  unlikely product of that stony soil.
  And then there was no tree.
  Suddenly, with no intermediate stage, in the place of the succulent green
  shape stood an architectural pillar, stocky, yellowing and fluted. Only the
  subtlest hint of the laurel tree remained, in the outline of the sharp-
  toothed, lance-shaped leaves carved around the base and the capital. The
  pillar stayed there for a moment, rather as a dragon-fly waits for its
  wings to dry in the sun. And then, with a chuffing, whirring sound, it
  dissolved from sight.
  The Monitor rose from the console and turned to the Doctor. 'The code is
  being compiled.'
  'Thank you, Monitor. I'm certainly looking forward to having a properly
  functioning TARDIS.'
  'Is this business going to take long?' Tegan demanded.
  The compilation would only take a matter of minutes, the Monitor assured
  them. This wasn't enough to calm Tegan down - nothing was. The Doctor, who
  still needed to clear up some points of detail with the Monitor about how
  
  the new figures were to be re-entered into the TARDIS system, appealed with
  a silent gesture to Adric. Do shut her up, his glance suggested.
  'It's not the Doctor's fault you wandered on board,' the boy said, matching
  Tegan's aggression with a little of his own. He contrived at the same time
  to draw her to the window, well away from where the Doctor and the Monitor
  were trying to have a civilised discussion.
  'Wandered? That ship was deliberately disguised as a police box. Talk about
  flying under false colours.'
  'Yes, I'd better explain about the TARDIS. You see, there's this thing
  called the chameleon circuit. It's simplest to look at it as a sort of
  logical gearing between the real-world interface and the internal quasi-
  dimensional continuum . . .' In mind-numbing detail, Adric began his
  discourse.
  Below the window the winding streets bristled with whispers and the clack
  of abacuses. In each cell entrance sat a Logopolitan, flicking his beads
  and intoning the information on to the next. The cells were the simplest of
  living quarters: a pallet on the floor, a few cooking implements hanging
  from hooks on the wall, and around the perimeter of the small white-washed
  room a neat collection of rectangular tablets that might have been the
  Logopolitan equivalent of books.
  One cell in all that winding chain was more elaborately furnished than the
  rest, although the occupant sitting at the entrance was too absorbed in the
  business of 'the Numbers' to realise it at the time. Behind him, at the
  rear of the cell, a stout, yellowing, fluted pillar had formed, reaching
  from roof to ceiling.
  The savage sizzling sound that echoed round the cell went unheard on the
  street outside, drowned beneath the rising susurration. Quite suddenly, the
  stool where the Logopolitan had been sitting was empty; the abacus had
  fallen to the floor. Beside it lay the occupant, immobile, eyes staring at
  ceiling, diminished to the size of a doll.
  While the whispers and clacking of abacus beads rose to a pitch, Adric was
  coming to the end of his short lecture on the chameleon circuit's
  functioning - or rather, reasons for not functioning. He had told her
  everything he knew on the subject, and what he did not know he had
  invented. At least it kept Tegan quiet until the Monitor returned from the
  console with the results of the compilation.
  'This will restore your chameleon circuit, Doctor,' said the Monitor.
  'Splendid, Monitor.' The Doctor took the data block. 'The TARDIS and I have
  been looking forward to this.'
  They were moving towards the door when the Doctor paused to look around
  him. 'You know, Monitor, there's something rather familiar about this room.
  But none of this was here last time I came.'
  'Your extensive travels put us stay-at-homes to shame, Doctor. Doubtless on
  one of your trips to the planet Earth you have visited the Pharos Project.'
  The Doctor snapped his fingers. 'Of course, the Pharos Project!' Then he
  realised he was no wiser, and had to ask 'What about the Pharos Project?'
  'And what is a Pharos, anyway?' Adric interjected.
  The Doctor was strong on Ancient Greek and replied before the Monitor had a
  chance to speak. 'Means a lighthouse. It's the name of a famous Earth
  project designed to transmit messages to remote planets.'
  'I understand they're trying to get intelligent life to respond,' the
  Monitor added.
  The Doctor smiled. 'But the life is too intelligent to do that before it
  knows what the Earth people are up to!' He was looking round the room
  again, and suddenly turned to the Monitor. 'Of course! This is almost
  identical to the Pharos computer room . . .'
  
  'I always thought you underestimated our Logopolitan skills,' said the
  Monitor with some pride. 'It's a perfect logical copy.'
  'Block transfer computation!' exclaimed Adric, not wanting to be left out
  of the conversation.
  'That . . . and a little more,' the Monitor agreed. 'You see, structure is
  the essence of matter.'
  'And the essence of structure is mathematics!' Adric added excitedly. He
  had grasped the point, and was keen to let everybody know it. By
  mathematically modelling the Pharos Project in sufficient detail and
  supplying the necessary raw energy, the Logopolitans had been able to re-
  create whole sections of the Earth structure on their own planet.
  On the steps down to the street the Doctor said, 'In that case, Monitor,
  you must be able to model any space/time event in the universe.'
  'Yes, true,' replied the Monitor modestly. 'But for the moment let's
  content ourselves with solving your little problem, Doctor.'
  No wonder they think so little of travelling, the Doctor mused to himself.
  On their journey back to the TARDIS the party gathered another following of
  flowing-robed Logopolitans. The Doctor drew the Monitor out of earshot of
  Tegan and Adric and said in a low voice 'I wonder if I can ask you a very
  special favour, Monitor?'
  'My dear Doctor . . . of course.'
  'I need this repair rather urgently,' said the Doctor, choosing his words
  carefully, 'because what lies ahead for me is . . . not for them. I'll have
  to leave them here, Adric and the girl. Would they be too much of a
  burden?'
  'I'm sure we can make them comfortable, Doctor.' The Monitor was puzzled,
  but it would have been a breach of etiquette to press questions.
  They had arrived at the TARDIS a little ahead of the others. The Doctor
  turned to his old acquaintance. 'I'll be back when I can. Which, to be
  frank with you, Monitor, will be soon - or not at all.'
  The Doctor's handshake was firm. He lowered his voice and added, 'I hate
  farewells. I hope you won't mind a small deception to keep this simple.'
  The Monitor understood immediately. 'You don't want them in the TARDIS with
  you?'
  Tegan and Adric caught up with them at this point, in time to hear the
  Doctor say, as if in reply to a remark of the Monitor's, 'Dangerous, eh?
  How dangerous?'
  The Monitor took his cue. 'Well . . . there's a chance the computation may
  produce . . . an instability.'
  The Doctor seemed to take a moment to ponder the question. Then he turned
  to Adric and Tegan. 'An elementary eggs and basket situation, wouldn't you
  say? Not to put all of the one in the other.'
  Adric tried to protest, but the Doctor persuaded him that even though there
  might be only one chance in seven hundred million of the process going
  wrong it was still silly to jeopardise more lives than necessary. Tegan saw
  the sense of that. Then, with the tiniest wink to the Monitor the Doctor
  disappeared through the blue double doors.
  Adric wouldn't let the matter rest. He turned to the Monitor. 'Then the
  Doctor is in danger? He said he was expecting danger - great danger, he
  said.'
  The Monitor smiled at Adric's agitation. 'A simple precaution. There is
  very little that can go wrong.' But seeing the alarm still on the boy's
  face he felt compelled to add: 'In fact, I must confess, nothing at all . .
  . I'm afraid I misled the Doctor in order to have the pleasure of your
  company while he engages on this mundane task. Now, perhaps you'd like to
  see more of Logopolis . . .'
  'No offence to you personally, but I'd prefer to see a lot less of it.' The
  Monitor's high diplomacy calmed Tegan, but it didn't stop her speaking her
  mind. 'Can you give me some idea how long we're going to be delayed here. I
  do have a job to do.'
  
  Adric apologised to the Monitor for his brash companion. 'I'm sorry. She's
  upset . . .'
  'Too right I'm upset,' Tegan declared. 'Wouldn't you be?' But if she was
  honest with herself she had to admit it was kind of exciting too. At the
  interview for the job they had asked her what her hobbies were, and she'd
  said 'Flying and travelling'. If that committee of stiff-necked personnel
  officers could only see her now!
  'That's very odd,' said Adric. 'It looks like . . . Nyssa!' He was peering
  past Tegan at some distant point behind her. She turned to see a small
  female figure standing on the skyline, right on the edge of the plateau.
  She seemed to have appeared from nowhere.
  The girl began walking towards the group round the TARDIS. And then she
  waved.
  Adric's mouth opened in astonishment. 'It is Nyssa!'
  The figure was running now. 'It's the girl who helped us on Traken,' Adric
  had time to explain, before Nyssa's arms were wrapped round him in an
  embarrassing hug of greeting.
  Tegan shook Nyssa's hand. 'Hi, I'm Tegan. Did they hijack you too?'
  The brown curls bounced around her pale young face as Nyssa shook her head.
  'A friend of the Doctor's brought me. He's here somewhere.'
  They looked around, but there was nobody but themselves and the
  Logopolitans.
  'A friend of the Doctor's?' asked Adric. 'Are you sure?'
  Nyssa's serious round eyes echoed surprise that he should doubt her word.
  'Of course. Is the Doctor here?'
  Adric pointed to the TARDIS, and Tegan added, 'He's trying out some kind of
  new trim for the machine. Have you seen inside that thing? It's the most
  amazing . . .'
  Tegan broke off abruptly, struck by something about the appearance of the
  TARDIS. During the arrival of Nyssa the Monitor had drawn closer to it,
  some doubt creasing his normally smooth features. Tegan looked at the time
  machine, unable to define what it was that was so evidently wrong. But
  turning to Adric and Nyssa she realised that they saw it too.
  The colour was too bright! And as they watched, it quickly became brighter,
  until it was fluorescing violently.
  At first Adric wasn't convinced it was a fault. 'It's the chameleon
  circuit. The Doctor's reprogramming it...,' he explained to Nyssa. But they
  could all see the look of alarm on the face of the Monitor and his fellow
  Logopolitans.
  Adric rushed to the Monitor's side. 'What's the matter?'
  'A transfer instability. It may be only momentary.'
  The Monitor seemed to be right. The fluorescence was visibly dying down.
  Instinctively, Adric, Nyssa and Tegan pressed forward, but the Monitor
  gestured to them to stay back.
  'Something is wrong!' Adric cried.
  At first it seemed like a trick of the light, some reaction of the eyes to
  the fluorescing. But as they watched it became clear without any doubt. The
  TARDIS was smaller!
  Tegan turned to the Monitor. 'You'd better do something,' she snapped.
  The Logopolitan shook his head in dull amazement. 'I don't understand . . .
  I don't understand . . .'
  'Look!' Nyssa exclaimed, although all eyes were already on the TARDIS.
  'It's still shrinking!'
  Alarm was spreading among the gathering of Logopolitans, who were drawing
  back from the sight. The TARDIS was now no taller than a man's height, and
  still diminished slowly as they watched.
  Adric grabbed the Monitor's arm. 'But the Doctor's in there!' he shouted.
  At a distance from the horrified crowd, elevated by the height of the
  smooth fold of rock on which he stood, the translucent watching figure
  remained immobile, waiting his time. And he knew that time was coming. But
  
  not yet - not quite yet.
  7.
  The Doctor's young friends pressed in around the Monitor, and Tegan's voice
  was louder than the others. 'It's your numbers doing this. You must be able
  to do something to put it right.'
  'Quick! Please, we must get him out of this!' Adric demanded, tugging at
  the Monitor's sleeve.
  A greyness glazed over the fine features of the Logopolitan. 'This is
  unheard of . . . A fault in the computations?' He pushed his fingers, some
  ornamented with simple rings, through the neat silver curls of his hair.
  Then the moment of hesitation was over. In a voice crisp with authority he
  spoke to the distressed crowd around him. 'Collect the visitor's machine.
  The honour of Logopolis is at stake.'
  And Adric thought he heard him add under his breath, 'And more than our
  honour . . . much, much more.'
  The TARDIS was now no bigger than a large cabin trunk, and even a child of
  ten would have had to stoop to get in through the miniature door. It was
  still fluorescing intermittently, but its surface didn't seem to be hot to
  the touch when the Logopolitans hoisted gently it into a horizontal
  position.
  Nyssa had run forward to supervise the lifting of the TARDIS. Now as the
  procession swept towards the city she fell into step beside the Monitor.
  'What are you going to do with the Doctor?'
  The Logopolitan Leader turned his head towards her gravely. 'Our best. That
  is all we can do.'
  And they hurried on to the Central Register through the winding maze of
  Logopolis, not knowing if the Doctor, inside that shrunken and still
  shrinking toy, was alive or dead.
  The Doctor himself was little wiser. He had been only part of the way
  through the tedious business of reading the figures off the data block and
  keying them at the console when the room began to fill with an insidious
  buzzing sound, like an infuriated mosquito caught in a jam jar.
  It was then that the distortions started. He first noticed a curious
  truncation of the time column, as if he were looking down on it from the
  perspective of the ceiling. His own hands, working at the keyboard,
  suddenly seemed a long way off. The buzzing grew, until he wasn't sure
  whether his head was in the room or the room was in his head. As he folded
  to his knees the floor rose smoothly to meet him halfway, like a well
  filling with dark oil.
  An idea came swimming towards him through the thick buzzing blackness:
  dematerialise. Whatever was causing the spatial anomaly might be local.
  There was a chance of escape, if only...
  The console was a giant mushroom that towered miles above him. He tried to
  struggle to his feet against some huge pressure. But he fought it, and
  eventually in agonising slow motion his knees straightened, and he found
  himself thin and tall, stretched like an over-tightened violin string
  between ceiling and floor.
  His hand, almost an independent creature at the end of his long arm,
  managed to pull the dematerialisation lever. The buzzing continued to grow.
  He tried to conjure power from the auxiliary buttons arrayed around the
  lever, but still nothing worked - only the viewer screen, which was now
  filled with a jolting picture of rose-coloured rock perforated by shadows
  that the Doctor's brain only dimly registered as a hugely magnified image
  of a Logopolitan street.
  And still the buzzing grew louder and higher in pitch until his whole body
  
  vibrated to it. And then, as if the violin string had snapped, the Doctor
  staggered and collapsed to the floor.
  The procession of dark-robed figures hurried on with the tiny TARDIS.
  Logopolitan courtesy, and a real concern, made each one anxious to
  accompany the Doctor to the Central Register, so on this occasion the
  streets behind them were left rimmed with empty cells. There was, however,
  one cell on the route that was not empty.
  From behind a yellowing, fluted column set just inside one of the dwelling
  places a face appeared, dark and spikily bearded. The thin lips parted,
  uttering a chuckle dry as the dust that was still settling in the train of
  the receding procession.
  'At last, Doctor!' smiled the Master. 'At last I've cut you down to size.'
  The Doctor knew nothing of the proximity of his oldest and deadliest enemy,
  indeed at that moment he knew little of anything. The TARDIS viewer offered
  a juddering succession of clues: a sea of serious faces, pink stone walls,
  flashes of bright sky. The image of a large building, approached by a
  flight of steps, lurched across the screen. And then a carved stone
  staircase, followed by the sharp white light, streaming from the interior
  of a lofty room, where the jolting giant images finally came to rest.
  Gargantuan in proportion, the face of Adric loomed in, filling the viewer
  screen. Behind him the ballooning features of Tegan and Nyssa signalled the
  vast scale of their concern.
  The Doctor saw none of this. His crumpled figure lay at the foot of the
  screen, inert beneath the weight of that unstoppable buzzing.
  By the time they had reached the Central Register the TARDIS had been small
  enough for two Logopolitans to carry. They set it upright and now stood
  back, waiting for new orders from the Monitor.
  Adric, Tegan and Nyssa knelt around it. The fluorescing had died down, and
  in every respect the TARDIS looked entirely ordinary - except that there
  was now no room for anything larger than a new-born kitten through that
  doll's-house door.
  'Hold on, Doctor. The Monitor is going to help us.'
  But there was no point in Nyssa calling, Adric pointed out. The Doctor
  might be able to see his surroundings on the TARDIS screen, but due to a
  long-standing fault it couldn't carry sound.
  Adric straightened up and looked around him. He felt so powerless in this
  alien room with its high white walls and rectangular racks of equipment
  whose purpose he could only guess at. He remembered what the Monitor had
  said: it was a logical copy of the Pharos Project. Why had they made the
  copy of a computer installation when Logopolitan computations ran without
  computers?
  The Monitor was stationed in front of the long grey console. That part of
  the installation must be Logopolitan in origin, thought Adric, the hub from
  which 'the Numbers' emanated, and to which the computations returned. Just
  as he had done before, the Monitor was leaning forward, intoning into the
  black aperture that Adric had first mistaken for a screen.
  'Etra secque secque eram nol. Etra secque kayrie gorrock gorrock kayrie
  zel. Kayrie nerus nerus kayrie zel . . .'
  The sound was hypnotic. And then Adric almost jumped out of his skin as a
  sharp grating noise split the air close behind him. One component of the
  Earth technology had sprung to life, a flat cream-coloured box, the front
  panel of which now glowed with light. Adric deduced from the paper covered
  with figures that emerged from the top that it was a sort of primitive
  printing mechanism.
  
  The Monitor was beside him now, reaching to tear off the print-out. 'It's
  somewhere in the dimensioning routine,' their host pronounced, scanning the
  paper. 'We can trace it, if there's time.
  'Perhaps I can help?' Adric suggested. He explained about the Alzarian
  Badge for Mathematical Excellence - not boastfully, but just so that the
  Monitor would understand he wasn't dealing with an ordinary boy who would
  only get in the way.
  The Logopolitan Leader explained that the printer was producing a machine-
  code dump of the routine that had caused the trouble. 'Can you read Earth
  numbering?' he asked. He tore off the print-out and handed it to Adric, who
  studied it for a moment.
  'Yes,' the boy said. 'The Doctor taught me.
  'It's a copy of an Earth machine, so I'm afraid we have to make do with
  their clumsy symbols.'
  It was in hexadecimal notation, using Arabic digits up to nine followed by
  the first six letters of what was called the Roman alphabet, so that the
  first fifteen numbers could be represented by a single character. In some
  ways it was a complicated way of counting, instead of the more usual Earth
  notation which used only as many symbols as there are fingers and thumbs on
  the human hand. But ten is a very awkward number, the Doctor had explained,
  only divisible by two and five. The hexadecimal notation was based on the
  number sixteen, which can be halved four times, and then produces perfect
  unity.
  The Monitor signalled to Adric to follow him. 'I must check the External
  Registers. Read it to me as we go.'
  Tegan had been kneeling beside Nyssa, watching the TARDIS closely for the
  past few minutes. It was still shrinking visibly, though the rate seemed to
  have slowed. She saw Adric and the Monitor leaving the room, and scrambled
  to her feet to follow them. But in the doorway she stopped and looked down
  the length of the hall they had entered. One long wall that stretched away
  into the distance as far as she could see was lined with dark-robed
  figures, each seated before a console that was a scaled-down version of the
  Monitor's in the Central Register. They spoke earnestly into the apertures
  in front of them, filling the room with the rhythmic incantation of 'the
  Numbers'. As Adric and the Monitor moved slowly away down the hall, Tegan
  hung back in the doorway, appalled by the sight of all those earnest,
  joyless faces.
  The Monitor moved from work-station to work-station, looking over each
  shoulder and listening in. Behind him trailed Adric, reading aloud from the
  print-out. 'Zero-A, Zero-four, Zero-Zero, nine-two, two-C, eight-seven . .
  .'
  They had turned a corner and passed through a doorway to enter a second
  similar room. Adric was barely conscious of his surroundings; it took all
  his concentration to read accurately from the paper in his hand. The
  Monitor's progress was slow and deliberate; only once did he hold up his
  hand to interrupt Adric's flow as he leaned over a fellow Logopolitan to
  exchange a few whispered words.
  He returned to Adric shaking his head. 'I'm sorry, I thought we had found
  something. It's somewhere in this sub-routine . . . somewhere.' He paused
  to look up and down the room, and Adric took the opportunity to survey the
  perspective of hundreds of whispering workers hunched before their
  consoles.
  'But Monitor, why do you need so many people? I still don't understand why
  all this can't be done with machinery?'
  'For many uses machinery is unsurpassed. But Logopolis is not interested in
  those uses. Block transfer computations cannot be run on computers.'
  'Why not?' the boy asked.
  'Our manipulations of numbers directly change the physical world. There is
  
  no other maths like ours.'
  Adric was surprised by the weight of sorrow in the man's voice. If he
  hadn't wanted so eagerly to know more, Adric might have had the tact to
  stop pressing his questions. 'You mean the computations themselves would
  affect a computer?'
  'Change its nature and cause it to malfunction,' the Monitor confirmed.
  'Only the living brain is immune.'
  'But you have a computer out there. You were using it.'
  'To record the code, and prepare new algorithms, yes. But we must never run
  our programs on it.'
  Adric scanned the print-out in his hand with new respect, and the Monitor,
  seeming to take this as an indication that they had rested enough, said
  'Perhaps we can continue . . .?'
  Adric felt a surge of panic. In the process of resting his eyes from the
  hard black print he had completely lost his place among all those figures
  that, he had to confess, meant nothing to him.
  The Monitor must have realised Adric's predicament. Gently, without having
  to consult the print-out, he said, 'We had reached zero-seven, zero-four,
  A-zero, three-zero, three-eight. We should be somewhere towards the end of
  the third block.'
  The silver-haired Logopolitan was smiling at him. Adric's pulse slowed, and
  he found his place again. Together they moved on down the long row of
  seated workers.
  The Doctor stirred and tried to lift his head. Even in his coma, immobile
  within the black winding-sheet of unconsciousness, the persistent sound,
  screwed up now to the pitch of pain, had somehow penetrated his awareness.
  Some fierce red luminosity swam in the darkness behind his eyes; it sapped
  the strength from his neck, and his head sank once more onto the TARDIS
  floor.
  If he had been able to open his eyes he might have seen, imaged on the
  viewer screen, the Logopolitan devices Nyssa had identified as
  loudspeakers. From the distorted perspective they seemed like giant steel-
  gauze hands cupped protectively around the tiny time machine. The gauze
  vibrated slightly as the energy pulsed through it.
  The deadly buzzing began to fade. Quite suddenly it stopped altogether. In
  the silence that fell like soft snow, the Doctor opened his eyes.
  There had been nothing out of place in the Registers, the Monitor was sure
  of that. The secret was out here in the deep and winding streets, alive
  with whispers and the click of abacus beads. But there were far too many of
  them. They could never check them all in time.
  Still reading from the print-out, though noticeably flagging now, Adric
  walked close beside the Monitor. He had become almost hypnotised by his own
  incantations. 'Eight-three, zero-three, A-three, three-seven, two-B, two-B,
  three-F, zero-D...' The paragraph of figures came to a conclusion in one
  more restful island of white space on the page before his eyes. 'That's the
  end of the third block', he told the Monitor.
  The Monitor was turning from side to side as they walked, glancing at the
  bowed, seated figures and the abacuses in the entrances that lined the
  street. He dipped his head to Adric in acknowledgement and said 'The work
  is wearying to those unused to it, but we must continue.'
  Adric took a deep breath and began again. 'Fourth block begins... Zero-
  three, zero-two, zero-zero, F-eight...'
  'Zero-zero, E-eight, I think,' the Monitor corrected, without interrupting
  his surveillance.
  The Monitor was right; Adric had misread the figure. 'Sorry, E-eight,' said
  Adric, wondering at the precision of detail held in that smooth grey head.
  
  'It is difficult, I know,' said the Monitor, putting his hand on Adric's
  shoulder. 'But accuracy is of vital importance...'
  Meanwhile in the Central Register a small group of the Logopolitans that
  Tegan had noticed conferring with the Monitor earlier were setting up a
  pair of large flat devices on either side of the TARDIS. They looked a
  little like portable screens.
  'Some sort of sonic projectors,' Nyssa suggested, raising her soft, clear
  voice a little over the sea-shell sound of myriad whispers that washed into
  the room from the Registers beyond the doors.
  Tegan was puzzled. 'What's the good of that?'
  'They must be creating a temporary zone of stasis around the TARDIS. But
  I'm afraid I don't understand their science.'
  'That goes double for me,' said Tegan. The Logopolitans had waved them
  politely back from the TARDIS while they set up their screens. Now Tegan
  was steering Nyssa towards one of the doors. 'But one thing's clear as
  daylight. Come and take a peek in this room here...'
  She pointed through the doorway to the External Register, and for the first
  time Nyssa saw the source of the echoing whispers. 'They all seem very
  dedicated,' she said, watching them.
  'Dedicated! That's one way of looking at it. You know what I think? I think
  it's sheer exploitation. Just look at their faces.'
  'They certainly all seem very serious,' Nyssa agreed. 'But I've seen that
  look on my father's face - intense dedication. These people are scientists.
  They're trying to help the Doctor.'
  'If you ask me they must be under some huge threat to keep them so hard at
  work,' Tegan said. 'Not that it seems to be doing the Doctor any good.' The
  two girls were walking back to where a knot of Logopolitans were gathering
  around the TARDIS. Some of the group stepped politely aside as the girls
  approached.
  Nyssa stopped in front of the TARDIS, measuring it with her eye.
  Tegan had noticed the same thing. There was no doubt about it: the TARDIS
  had stopped shrinking.
  Adric's throat was very dry now, and he spoke with obvious effort.
  '...eight-nine, nine-A, zero-A, one-one, E-seven...'
  Once again the Monitor stopped him. It was the fourth time in the past
  three streets. Adric was becoming an unreliable reader. 'E-nine,' the
  Monitor corrected, a little testily.
  Adric stared at the paper in front of him. The little black figures were
  starting to dance in front of his eyes. 'Sorry,' the boy said. 'E-nine,
  three-three...' But he broke off almost immediately. 'Did you say "E-nine"?
  It says E-seven here.'
  The Monitor seized the paper. 'You're right, E-seven. And the next three
  numbers are wrong...' He looked rapidly up and down the street, calculating
  the shortest route. 'Come on, this way.'
  Tegan's elation at finding that the shrinking process had come to a halt
  was quickly replaced by a renewed sense of despair. 'The TARDIS isn't much
  use to anybody that size, stable or not,' she said to Nyssa who was
  kneeling beside her. If only one could see in through those small black
  windows.
  'Perhaps it gives us some time,' said Nyssa, after a moment.
  'Time to do what? We don't even know if he's alive in there.'
  But the Doctor was alive. After his ordeal the very idea astonished him,
  
  but, as he sat up, holding his head in his hands, the suspicion shaped
  itself into a theory which hardened into a fact. Yes, he was alive!
  The moment he saw the Logopolitan devices magnified in the viewer screen he
  realised what had happened. 'They've arrested the dimension spiral. Things
  are looking up.'
  The street seemed narrower than the others, and the sounds quieter. The
  Monitor stopped at the junction to make sure of his bearings.
  'This is the street. The error should be somewhere here...'
  They advanced side by side, just as they had in so many streets before. But
  now the Monitor moved more slowly, like a cat that can smell its prey.
  The first two cells on the left-hand side of the street were occupied by
  chanting Logopolitans, busy at their abacuses. But the third cell stood
  empty.
  Adric noticed it first. The shrunken body lay carelessly beside the vacant
  stool like a neglected child's toy. There was a faint, fresh smell, like
  ozone, in the air.
  The next two cells revealed the same gruesome story. Horrified, the Monitor
  looked up from the tiny body he had knelt beside. 'Sabotage,' he said
  darkly.
  'Murder,' corrected Adric. 'That's far worse.'
  The Monitor stood up, and his voice was low and harsh. 'Interference with
  the workings of Logopolis. That could be the most dangerous crime in the
  universe.'
  At the time it struck Adric as odd that the Monitor should raise his eyes
  as he spoke, looking not along the length of the street, but fixing his
  gaze quite definitely on one particular point in the sky.
  What the Monitor was looking at Adric was soon to discover. But the boy
  recognised at once the shadow of terror that lurked beneath the surface of
  those leaden eyes.
  8.
  Adric looked up and down the street, alert for any sign of the being he had
  come to hate so much, and all the time trying to keep his gaze from
  drifting back, as it kept doing in fascinated horror, to the tiny corpses
  of what had once been Logopolitans. The Monitor meanwhile had picked up one
  of the abacuses and was rattling off some rapid calculations, pausing
  occasionally to make emendations to the print-out.
  And if he had seen the Master? Adric wondered what he would have done, and
  realised how much he had come to depend on the Doctor's wisdom. Without him
  it was hard to reach a decision - a state of mind he was certain the Doctor
  would not condone. Adric vowed then and there to make it his mission to
  find the Master.
  Almost as if he had conjured up the image from his mind, a figure appeared
  at the far end of the street. It was standing on the terrace of pink rock
  above the dwelling places, and was clearly no Logopolitan. Instead of the
  flowing dark robes, it wore - or rather, was imbued in the aura of - a
  white, shimmering translucence that seemed to fade even as Adric looked. It
  was the figure the Doctor had negotiated with on the bridge!
  The Monitor had been too involved in his own work at the abacus to see any
  of this. Now he got up briskly, rolling up the print-out. The movement
  distracted Adric's gaze for a fraction of a second, and when he looked
  again there was nothing where the watching figure had stood but rocks and
  
  the shadows of rocks.
  'Quickly!' said the Monitor. 'We must return to the Central Register at
  once.'
  At least the hideous buzzing had stopped and the console room now looked
  its old self again. But the exaggerated gravity that slowed down his
  movements, and the giant faces of Nyssa and Tegan in the frame of the
  viewer screen were enough to remind the Doctor that he and the TARDIS were
  still literally in a tight squeeze.
  If the error was in the dimensioning routine there was a remote possibility
  of being able to dematerialise by shorting out the chameleon circuit
  altogether. It was a dangerous business, but it was something to do!
  Struggling against gravity as he moved towards the console, the Doctor
  tried to draw together in his mind the remnants of his knowledge of time
  map structuring. Romana's help would be useful, he thought. Or come to
  that, anybody's.
  He went to work, overlooked by the girls' huge unseeing faces. Grounding
  the chameleon circuit was a massive task - the whole Real World gearing
  would have to be unharnessed before he could get to the necessary
  components - and the result was risky at best, and at worst unthinkable. In
  the heart of his two hearts the Doctor must have realised that the only
  real chance of help was from outside. Yet a streak of stubbornness was
  driving him to a course that might only add to the danger. Wielding the
  sonic screwdriver he began to remove the first panel of the console.
  The screen-like objects on either side of the miniature TARDIS were
  emitting a faint hum, Tegan realised after she had been kneeling beside
  them for a while. Nyssa had explained that they were probably sending out
  some sort of cancellation wave to hold the effects of the scrambled
  dimensioning in check.
  And a lot of use that was. Tegan looked in despair at the tiny vehicle that
  had spirited her to this strange and remote place. It had already caused
  her such distress that she didn't care if she never saw it again. Except
  that it was her only way back to civilisation. And the Doctor was in it.
  Adric broke into her thoughts, rushing in through the door with the
  Monitor. 'The Monitor's done it,' the boy exclaimed as Nyssa and Tegan
  scrambled to their feet. 'He's found the error.'
  The Monitor quickly explained as much as was necessary. The error was in
  Block Four of the dimensioning routine, and somehow the correct figures had
  to be got to the Doctor so that he could re-enter them into the console.
  'Assuming he's alive in there,' said Tegan, taking the amended print-out
  from the Monitor.
  It was her idea to hold up the printed sheet towards the TARDIS, in the
  hope that the Doctor would be able to read it on the Viewer Screen. 'Let's
  just hope he knows what to do,' she added.
  Adric helped her unroll the print-out. 'He will. He's the Doctor!'
  And his own words reminded him of his vow to track down the Master. How
  long they would have to wait until the Doctor was out of the TARDIS, or
  what state he would be in when he finally emerged, were unknown quantities.
  Meanwhile the evil Time Lord was somewhere near, stalking the Logopolitan
  streets. Adric jumped up. 'I've got to go back,' he said. 'The Master . . .
  he's out there.'
  Nyssa caught hold of his arm. 'The Master? I'm coming with you.' Nothing
  would put Nyssa off. 'I came here to find the Master I must know what's
  happened to my father.' Adric saw the determination in those serious olive-
  green eyes. He took her hand, and, with a wave to Tegan and the Monitor,
  they ran down the stairs towards the street.
  
  Up until that moment the Doctor had been sitting under the console,
  studying one of the small components littering the floor around his feet, a
  collection of multi-coloured objects that might have been mistaken for
  infants' toys.
  It was no pleasure disassembling the Real World gearing. There are some
  things in life, the Doctor thought to himself, that shouldn't be tampered
  with - and the TARDIS was certainly one of them. She was so temperamental
  that it was almost impossible to isolate a fault without generating a
  number of others.
  Then he reminded himself that it was because of the TARDIS he had come to
  Logopolis. Funny, that. You put up with its tantrums through the centuries,
  and then a sort of vanity drives you to try and improve the old vehicle. To
  tamper, in fact. But in that he had been out-tampered by the Master.
  'The cheese-board is the world, and the pieces,' the Doctor said aloud as
  he began to dislodge the next component in the chain, 'are the phenomena of
  the universe. As my old friend Huxley used to say.' Or was it chess-board?
  Yes, chess-board, of course . . . And then he remembered with a chill the
  rest of what Huxley had said. He had been speaking of the battle of science
  to wrest knowledge from that stubborn opponent, the Nature of Things. But
  the words might quite as well have applied to the Master. 'The opponent
  never overlooks a mistake, or makes the smallest allowance for ignorance.'
  Ignorance was the word. There was no denying it: he was an ignorant old
  Doctor, and he had made a mistake.
  He lifted his eyes again to the viewer screen, but the earnest young faces
  were gone now, he noticed with some disappointment. Now the Logopolitans
  were blocking the viewer with a sheet of paper covered with numbers.
  His head had actually ducked back under the console before he realised.
  Numbers! He jumped up again - or rather tried to. If the exaggerated
  gravity hadn't slowed the movement he would certainly have cracked his head
  on the under-side of the console.
  Magnified on the screen, the Monitor's precisely hand-written emendations
  stood out clearly against the machine print. Very pleased with life, the
  Doctor reached for the data block.
  'The mark of the Master,' said Adric with a shudder, pointing out to Nyssa
  the doll-like, dead Logopolitans. He had managed to trace his way back to
  the street where the Monitor's search had wound to its ugly conclusion.
  'He must have added his own voice to the Numbers, and corrupted the
  Doctor's code,' said Nyssa, the anger flashing in her eyes. Adric
  remembered that this was the man who had almost destroyed her planet, and
  who was almost certainly responsible for her father's disappearance -
  though in what way the Doctor hadn't explained.
  Adric pointed out the spot where he had seen the translucent figure that
  seemed to have followed them from the planet Earth.
  'The Master?' Nyssa asked. Neither of them, they realised, knew what the
  Master looked like.
  'Him . . . or something worse.'
  They had begun to explore beyond the end of the street, where a T-junction
  lead off out of sight in both directions. The susurration and clack of
  beads came more strongly from their left, so Adric presumed that way lead
  back to the centre.
  For some reason they both had an instinct to explore to the right. It was
  nearly the undoing of both of them.
  The trouble was, there was no way of knowing if the Doctor could see the
  figures, and if he could, whether he was in a position to do anything about
  it. Her aching arms and the crick in her back told her she had been holding
  
  up the print-out quite long enough, but Tegan had the continuing feeling
  that if she stayed kneeling in front of the TARDIS just a little bit longer
  it might make the difference of life and death to the Doctor. To say
  nothing of whether she ever got home or not.
  The Monitor arranged a compromise. But having instructed two Logopolitans
  to hold up the sheet of paper while Tegan stretched her legs, the last
  thing the Monitor expected was to find himself being marched by this
  imperious young woman over to the door that lead through to the External
  Register.
  'Would you mind explaining something to me?' she demanded, indicating the
  long row of earnest, pallid faces seated before the consoles. 'Back home in
  Brisbane we'd call a place like that a sweat-shop. What's going on?'
  The Monitor seemed not to understand. Tegan explained the phrase 'sweat-
  shop', and went on: 'You're not going to tell me they're all working of
  their own free will.'
  'Academic research', said the Monitor, 'commands its own dedication.'
  'You can't tell me this is just academic research. Look at them - they're
  grey with worry.'
  'And what about you, Tegan - are you dedicated to your work?'
  Tegan admitted she was top of the training course for the airline job. But
  that was different. 'We all enjoyed it. These people are being forced into
  - whatever they're up to. They don't smile, they don't talk.'
  The Monitor spread his hands in a careful gesture of incomprehension.
  'Their language is the language of the Numbers. It is their talent and
  their passion, and their work is very serious. They have no need to smile.'
  Tegan was aghast. 'No need to smile!'
  Touching her arm, the Monitor steered her gently back into the Central
  Register. 'And as for speech,' he continued, closing the door behind them,
  'we are a people driven not by individual need, but by mathematical
  necessity. The language of the Numbers is as much as we need.'
  'But if they can't talk at all . . .' Tegan broke off, looking in the
  direction of the TARDIS. It was fluorescing again. In panic she ran to it,
  snatching the paper from the Logopolitans. She was about to turn on them
  for neglecting their job, when the Monitor stepped in.
  'The Doctor's reversed it,' he said, delight brightening his parchment
  face.
  It was true! The TARDIS was growing larger as they watched.
  It was a street with few cells, on the very edge of the city where the
  whispers were quieter. Adric and Nyssa were running; for Adric had been
  almost certain he had seen the translucent figure again.
  Nyssa's hair coiled in the wind as she ran beside him. 'Where?'
  'Never mind - follow me,' said Adric, racing ahead.
  She was about to comply when the hem of her skirt caught in one of the
  small thorny plants that grew along the pink rock wall. She paused to lean
  against a nearby pillar and unhook herself. The tiny tenacious barbs were
  reluctant to let go, and she had to sit on the base of the pillar, which
  was decorated with a frieze of carved leaves, and lean back against its
  squat, fluted column while she picked the thorns out of her skirt.
  When she looked up, Adric had turned the corner - in which direction she
  couldn't be sure. Rising to follow, she became aware of a pair of eyes
  watching her from the gloom of the cell. The eyes were familiar. She raised
  her hand to shade out the light and peered into the shadows.
  'Father?' She held her breath.
  The figure in the shadows stepped forwards, and Nyssa was overjoyed at what
  she saw.
  'Nyssa! Nyssa, my dear,' said the Master, holding out his hands to her.
  He seemed changed; younger than she remembered him, his silver hair now
  dark and his face leaner. But Nyssa could never mistake her father's voice.
  
  They walked through the narrowing streets until they came to the gullies
  that led out onto the plateau, and all the while she listened to that low
  voice as it unfolded new ideas for research, plans for the future and
  stories of past deeds. She realised as they stopped to look out over the
  distant rosy rolling hills that she had been so caught up in the joy of
  seeing him again and hearing that dark hypnotic voice that she had scarcely
  taken in a word.
  'What is this "mission" of yours, father?' She reached out to touch his
  hand, and was surprised to find it icy. 'Tell me. You seem so changed by
  it, so cold, somehow.'
  'Logopolis is a cold place. A cold, high place overlooking the universe. It
  holds a single great secret, Nyssa. Which you and I will discover
  together.'
  'And the Doctor,' she added. 'The Doctor can help us.'
  'Oh yes, the Doctor can certainly help us.' He smiled a thin smile. Then he
  withdrew his hand and said suddenly, 'You must return to him.'
  'I don't want to be parted from you, father.'
  'No need to be.' There was a chuckle in the voice of the man beside her and
  from his coat he brought out an armlet. Chased into the gold was a design
  of leaves sprouting in pairs along a stem studded with small bright stones.
  He clipped it on her upper arm. It seemed to catch at her flesh, making her
  wince momentarily with pain. 'This will keep us in mind of each other,' he
  said. And then he was gone, leaving her to wander back to the city alone.
  At last the TARDIS was full-size again! It fluoresced briefly for the last
  time, and then the door opened and the Doctor stepped out.
  'Monitor, I can't thank you enough.'
  'Tegan, too,' said the Monitor. 'But please, Doctor. There's really no need
  . . .'
  The Doctor enthusiastically shook the Monitor and Tegan by the hands
  nevertheless. 'No, you two have saved my life. There have been quite enough
  deaths already.'
  The Monitor was surprised. 'You know about the deaths?'
  The Doctor was distressed to learn from the Monitor about the Logopolitan
  lives that had been lost. But he had been referring to Earth, intending to
  lead up to something that had to be said. He took the young woman's arm.
  'Tegan, your Aunt Vanessa . . .' he began.
  'Yes, how do you like that? She's probably back at the cottage by now, with
  tea and crumpets, while I . . .' She broke off, catching sight of the
  Doctor's grave expression. 'She's all right, isn't she, Doctor?'
  The Doctor told her the news as simply as he could. Tears welled up in her
  deep brown eyes. 'That dear, sweet lady...'
  They were standing by the window, looking out over the myriad streets
  carved into the Logopolitan rock. The Doctor fumbled in his pockets for the
  cleanest handkerchief he could find, and said, 'That's why I'm going to put
  a stop to the Master if it's the last thing I do.'
  Tegan blew her nose. The Doctor turned from the window and, looking round
  the big white room, said, 'There were one or two more of us. Where is
  everybody?'
  'Your companions went to hunt for this person called the Master,' the
  Monitor explained.
  'Idiots! Adric should know better by now.'
  The Doctor's explosion of anger brought Tegan back to something of her old
  form. 'He was only trying to help. He saw somebody out there.'
  The Doctor swept the common-sense response aside and, telling them to stay
  in the Central Register, and to be very, very careful, ran from the room.
  Tegan followed him to the door and watched him sprint down the sweep of
  carved stone steps that lead to the street.
  
  Adric had turned the corner and run the whole length of the second street
  before realising Nyssa wasn't with him. When he reached the spot where he
  had last seen her he called her name again. No responding voice disturbed
  the distant whispers.
  Adric searched like this for what seemed hours. When he finally found her,
  wandering in a daze quite close to where they had parted, she seemed
  oblivious of the time that had passed.
  'Did you find him?' was all she asked.
  Adric shook his head. 'We'd better get back to the Doctor.' After they had
  walked through several streets, during which time Nyssa had only answered
  in monosyllables his attempts to talk to her, he stopped and said, 'Nyssa?
  Are you all right?'
  A faint smile lit up her small round face. 'My father's here.'
  'Your father? So you found him!' Adric exclaimed.
  Nyssa seemed to hesitate. 'Yes . . . it was my father.'
  'But that's wonderful. What's he doing here on Logopolis?'
  She had been sworn to secrecy, so she said nothing of the 'mission'. But
  she did show Adric the armlet. 'It's too small for me. I've been trying to
  get it off . . .'
  It was certainly pinching into her forearm. But when Adric inspected it he
  was surprised to discover that the precious stones inlaid into the chased
  gold were electronically illuminated from inside. 'It's a sort of . . .
  communications device. Yes, it does look tight . . . '
  Tugging at it may have disturbed a loose connection, because it sparked
  suddenly. Adric jumped back, feeling a powerful electric shock. He
  recovered almost immediately, and was surprised to find that Nyssa had felt
  nothing.
  All she said was, 'I hope you haven't broken it.'
  He tried a second time to remove it. There was just enough room to get one
  of his thumbs under it, and he was experimenting with the best way of
  gripping it with the other hand when he noticed Nyssa's arm begin to flex
  in a curious mechanical way. The hand opened and with clinical precision
  began to advance towards his neck.
  'Hey, what are you doing? I'm trying to concentrate,' Adric laughed.
  The hand was closing on his throat. Adric was surprised at the strength in
  those small fingers, but the most extraordinary thing of all was that Nyssa
  herself seemed not to notice anything at all. Her face was averted,
  entranced while the steel grip bit tighter into his neck.
  And then he heard a voice he had thought he might never hear again.
  'Adric! Nyssa!'
  The Doctor was striding down the street towards them. The fingers around
  Adric's throat instantly relaxed, and Nyssa cried out with delight,
  'Doctor! You're free!'
  
  9.
  Adric's delight at seeing the Doctor again was tempered by a feeling of
  guilt at having abandoned him to the perilous instability of the TARDIS to
  go off hunting for the Master with Nyssa. The Doctor left them in no doubt
  that they were lucky to have survived the folly; and then as they hurried
  back to the Central Register, seemed prepared to drop the subject. There
  was one thing he wanted to clear up, though. 'Tegan says you saw him.'
  'Yes, here, in one of these streets,' said Adric.
  'What did he look like?' the Doctor asked innocently.
  Adric was confused. He had only once seen the Master, on Traken in his
  guise as the Melkur. And yet he knew by instinct. 'You know. The man you
  were talking to on the bridge . . .'
  'The man on the bridge?' repeated the Doctor.
  'Yes . . .' The boy hesitated, thrown by the Doctor's tone of irritation.
  Then it happened again - as if just thinking of that vaguely outlined
  watching figure were enough to conjure him up! Adric was sure he wasn't
  seeing things. The figure was at ground level this time, standing still and
  translucent at the far end of the street. The boy pointed. 'There, that's
  him.'
  Adric thought he heard Nyssa gasp, but turned to find her laughing. 'That
  can't be the Master . . .' she said. 'That's the man who brought me here
  from Traken. A friend of yours, Doctor.'
  Adric was astonished, but the Doctor confirmed her story with an uneasy
  nod. 'Yes, a sort of . . . passing acquaintance. He brought you here on my
  account.'
  Adric still felt some dread at meeting this creature whose presence he had
  once felt sure even the Doctor feared. But as they approached, some cloud
  must have shifted overhead, because a shaft of sunlight hit the spot where
  the figure had been standing. The gleam thrown back from the pink rock
  momentarily dazzled Adric. He blinked his eyes, and when he looked again .
  . . 'Doctor, he's gone!'
  Oddly the Doctor didn't seem surprised.
  Who was this dreamlike figure who seemed to be hovering on the edge of
  their existence? As they pressed on towards the Central Register Adric
  pursued the subject. 'I was almost sure it was the Master.'
  'I warned you against unnecessary guesswork,' snapped the Doctor.
  'But he was the man who told you bad luck was on the way.'
  'He was right,' said the Doctor. 'And worse to come.'
  Worse! Why was the Doctor so sure? 'And you believe him?' the boy
  persisted. 'Why?'
  'Because he is here,' said the Doctor, his eyes fixed on the route ahead.
  Like so much that the Doctor said it seemed to make no sense. It would have
  puzzled Adric more if he had known that on this occasion the Doctor was
  speaking no more than the exact and literal truth.
  It still didn't seem right to Tegan. She watched the serious faces of the
  two Logopolitans who had come to collect the stabilising screens around the
  TARDIS, and, while they silently wheeled them through into one of the
  External Registers, wondered if there would ever be any - well, fun - on
  Logopolis?
  The Monitor tried to tell her of the invisible joy that comes from selfless
  dedication, but she couldn't understand it. In a way it was presumptuous of
  her to try; Logopolis was a completely different civilisation from anything
  she was used to. And yet Tegan still had this feeling that the Monitor was
  
  concealing something.
  The two Logopolitans rounded a corner and wheeled the pair of screens
  through into the second External Register. Of the long row of Numberers
  busy chanting into the apertures, only one turned from his work to watch
  them pass. He wore the dark flowing robe of a Logopolitan, but he lacked
  the pale complexion, and his face was brightly animated above his sharp
  black beard. With the faintest chuckle the Master rose and followed the two
  screens.
  The door to the Technology Store opened to admit the screen-bearers. But
  before they could pass through, a discreet flash and short sizzling sound
  halted the screens in the doorway.
  Nothing had happened to distract the busy Numberers. Had they looked up
  they would have seen one of the two screens turn in the doorway to face the
  way it had come, manoeuvred by a single figure in dark flowing Logopolitan
  robes. A faintly sweet smell of ozone hung in the air. The two screen-
  bearers lay in the doorway, their corpses shrunken to the size of dolls.
  The Master took a small silver box from the folds of his robes and attached
  it to the rim of the screen. A change came over the long hall: all sound
  drained from the scene, and then one by one the Numberers froze into
  immobility. All that penetrated the deadly silence was a tiny chuckle of
  triumph.
  Beneath her aggressive exterior, which the Monitor assumed was due to
  feelings of insecurity in the alien surroundings, Tegan was clearly an
  intelligent young woman. But he judged hers to be a mind not drawn to
  abstractions: the objects of her thought were concrete.
  This presented a difficulty in the way of conversation while they waited
  for the Doctor to bring back Adric and Nyssa. The Logopolitan world was
  predominantly a world of thought; such solid furnishing as lay about the
  place were incidental to the life of the City. By way of compromise they
  settled upon a discussion of the screens, items of solid technology that
  had certainly proved useful.
  The Monitor heard the door behind them open. As if by way of illustration,
  one of the screens they had been discussing appeared there. He moved
  towards it, about to question its return. The man dressed as a Logopolitan
  was clearly an alien. The Monitor halted in his tracks; the newcomer
  radiated evil.
  'Please remain where you are,' said the Master. 'I have it in my power to
  bring Logopolis to a complete halt.'
  And Tegan's blood froze to hear again the chuckle that had first terrified
  her in the TARDIS cloister room.
  They were still some way away from the Central Register when Nyssa stopped
  suddenly. 'Listen!'
  'I can't hear anything,' said Adric. And then he realised. Logopolis, the
  city that buzzed with numbers and the clacking of abacus beads . . . was
  now completely silent.
  'Logopolis has stopped!' Nyssa exclaimed.
  The Doctor peered into the nearest cell. As they had come to expect, a
  Logopolitan was sitting in his customary place at the entrance. But this
  one was completely motionless and silent, his abacus lying unused on his
  lap.
  Adric saw the Doctor reach out to touch the still figure. To his horror the
  flesh crumbled away to dust as if it were a hollow, fragile shell.
  The Doctor straightened up. 'It's started already,' he said grimly. 'The
  Master's attack. I was vain enough to believe it was me he was after.
  Logopolis is his target.'
  
  There was nothing Tegan or the Monitor could do. The screen, with the
  Master's added silver device, was pointing into the aperture of the
  Monitor's console, pouring its lethal silence into the whole city.
  The Monitor's distress was evident in his voice. 'Turn that machine off
  immediately. You fool! You have no idea what you are doing.'
  The Master smiled. 'Merely emitting a sound-cancelling wave. Logopolis is
  now temporarily suspended, Monitor. The silence gives us an opportunity to
  discuss its future.'
  'No!' The monosyllable was full of pain. 'It won't have a future, and nor
  will anything else unless you stop now.' The Monitor was pleading. 'You are
  eroding the structure and generating entropy.'
  Tegan had no idea what was happening, but she could see from the Monitor's
  face that something had gone horribly wrong - something the Master had not
  anticipated.
  'An absurd assertion, Monitor,' said the Master, with an arrogant curl of
  his lip. 'I know the power of this device down to the last decibel.'
  'But you don't know Logopolis!'
  The Master stared back with cold, empty eyes. 'But I shall know it, shan't
  I, Monitor? Before I allow the fascinating sounds of life here to resume
  you will have told me all there is to know. Of the secret work you are
  doing here perhaps . . . I heard rumours of your plagiarism of the
  Earthling's fruitless Pharos Project. Why have you created a copy here on
  Logopolis, Monitor? The time has come for you to share your secret with
  me.'
  There was madness in the smooth controlled voice that made the Monitor move
  back instinctively, shaking his head. 'I cannot tell you. No one must know.
  That has been our firm decision.'
  So the Monitor had been concealing something! The thought flashed through
  Tegan's mind as she heard the Master say: 'Then we will wait until you
  change your decision. Patience is a particular virtue of mine.'
  'If you call killing the Logopolitans a virtue.' Tegan turned at the sound
  of the familiar voice. His scarf and coat flying, the Doctor strode into
  the room, followed by Adric and Nyssa.
  The Master's laughter fell like a shower of acid rain on the white-walled
  room. 'Killing them, Doctor? You expect me to believe that?'
  The Doctor certainly did. In a few terse sentences he gave an account of
  what they had seen in the street outside, and added, 'So you see, the
  Monitor's right, Master. Your spirit of free enterprise is more damaging
  than even you can imagine.'
  'Father! What are you doing?'
  There was a note of surprise in Nyssa's voice. She had been slowly walking
  towards the Master, and now she stood before him, reaching out, her round
  face a question.
  'That's not your father, Nyssa.' The Doctor gently took her arm and drew
  her back. 'Tremas is dead. Killed by the Master here!'
  'Dead!' She saw the truth in the Doctor's eyes, and turned to confront the
  object of his accusing finger. 'You've killed my father!'
  Again the Master's laugh grated on the still air. 'But his body remains
  useful.'
  Adric was astonished to see this small, aristocratic girl so brimming with
  icy anger. She tore herself from the Doctor's grasp and rushed at the
  Master. But as she was almost upon him a curious thing happened.
  The arm on which she wore her new gold armlet seemed suddenly to be
  suspended in the air, pulled up by some invisible hook. It jerked Nyssa
  back: she tugged at it, trying to reach the Master with the other hand. But
  the mocking face lay just beyond her flailing fingers.
  'I'm grateful to Tremas,' the Master sneered. 'Without this body I could
  not have conquered Logopolis.'
  'This isn't conquest - it's devastation,' the Doctor shouted.
  
  'Yes, you will destroy everything.'
  It must have been the note of terrible urgency in the Monitor's voice that
  made the Master hesitate fractionally before he said, 'You exaggerate,
  Monitor. Logopolis is not the universe.'
  'But it is! Logopolis is the keystone.' The Monitor's face was ashen. 'If
  you destroy Logopolis, you unravel the whole causal nexus!'
  'Causal nexus! You insult my intelligence, Monitor.' But the Master was
  less sure now. He paused before the Monitor, glowering into those opaque
  grey eyes, trying to read the purpose behind this preposterous suggestion.
  In the silence Tegan whispered to Adric, 'What's he talking about?'
  'Something's interfering with the law of cause and effect,' the boy
  replied. His gaze was fixed on the Master, who seemed about to strike the
  Monitor. Out of the corner of his eye he saw the Doctor rush forward.
  'Listen to him! The Monitor's right! We've seen it!'
  'Please step back, Doctor. Or . . .' The Master touched a button on the
  silver box attached to the screen. Nyssa cried out in pain as her arm swung
  round threateningly towards the Doctor.
  'Let her go,' said the Doctor between gritted teeth. But for safety's sake
  he took a step back.
  Adric was rasher than the Doctor. His anger drove any thought of the
  consequences out of his mind, and he dived for the screen, sending it
  flying across the room. At that moment a hand closed around his throat.
  'Nyssa! Let go.' Once again the small fingers dug deep into his neck. He
  screwed his head round to see blank astonishment in her eyes.
  'I . . . can't . . .' she cried.
  The Master voice was cool. 'That is a demonstration of the causal nexus,
  Monitor. The electro-muscular constrictor gives me complete control over
  that hand. Please replace the screen, Doctor. Or one of your young friends
  will eliminate the other.'
  The Doctor had no choice. Seeing him forced to do as the Master demanded,
  Tegan's anger boiled over. 'You revolting man. I wouldn't take orders from
  you if you were the last man in the universe.'
  'Which he may well be, if he carries on like this,' said the Doctor when
  the screen was in place again. 'Don't you see what the Monitor is telling
  us, Master? Logopolis isn't the academic backwater it seems, but somehow
  crucial to the structure of creation.'
  'I have never been susceptible to argument based on abstract nouns,
  Doctor.' The Master touched the silver box and Nyssa released her grip.
  The Doctor pointed to the door. 'Then come out into the streets and see
  what's happening.'
  His adversary stroked his beard with a gloved hand, considering the idea
  for a moment. Then he shook his head. 'No need for that, Doctor. I can
  demonstrate the continued functioning of Logopolis from here.' He reached
  towards the silver box. 'This device only creates temporary silence. And
  can be switched off.'
  The Master unclipped the box from the screen, and after a moment put his
  ear to the aperture in front of the console to listen.
  The Monitor had said nothing for a while. Now his voice was quiet and
  clear, with only a hint of a tremble. 'You will hear nothing. Local
  disruption of structure is already irreversible. Logopolis is dead.'
  The Master hesitated on the steps of the Central Register. Below him the
  street was beginning to silt up with a fine pink sand that cascaded down
  from the shifting rocks. Apart from the cracking and hissing of this
  motion, there was total silence.
  He ran down the steps, followed by the others. While the Master inspected
  cell after cell, ducking the intermittent showers of debris, the Monitor
  said softly in the Doctor's ear. 'We knew there was this danger. We often
  speculated on what it might be like.'
  
  The Master clutched at an abandoned abacus; it crumbled in his hands. He
  turned to the Monitor. 'You've done this deliberately. A ploy to deprive me
  of my prize.' As he spoke a nearby cell collapsed in a slide of rubble.
  'Don't raise your voice,' the Monitor warned. 'Nothing is solid now.
  Entropy has taken over.'
  The Master looked wildly round the street, as if trying to escape the truth
  of the Monitor's story.
  Tegan, who understood very little of this, tugged at Adric's arm. 'But
  what's he done?'
  Everything had begun to waste away when the Master interfered. That much
  Adric was able to explain. 'The Numbers. Somehow they were holding the
  whole structure together.'
  'The causal nexus broken? I don't believe it.' The note of defiance in the
  Master's voice was distinctly unconvincing now. But he went on: 'No,
  Monitor . . . this is some crude defence mechanism, a device to delude an
  enemy. Come, Nyssa, we'll wring the truth out of them.
  He punched a button on the silver box, drawing Nyssa towards him. But when,
  with a second button, he tried to elevate her arm . . . nothing happened!
  He stabbed at the box with an angry finger. 'It's not working! What have
  you done, Doctor?'
  The Doctor stared him out. 'Not me, Master - you! The entropy you released
  is eroding your systems too.'
  'Entropy? Absurd . . . the power is weak . . . some freak interference.
  Increase the power.'
  'More power will only speed the collapse,' said the Monitor quietly.
  The Monitor was right. The ornament on Nyssa's arm suddenly shattered and
  crumbled to the ground. The Master stopped dead, staring at the remnants of
  the armlet. When he looked up again, it was at the Monitor, who had begun
  to speak with slow deliberation.
  'The things around us are now no more than husks of themselves. From this
  point the unravelling will spread out until all the universe is reduced to
  a uniform, levelled nothingness.'
  'So it's true!' the Master cried.
  'Don't move. Anybody . . .' The Monitor's voice came as a whisper.
  Instinctively they all obeyed. Even the Master stood in silence, surrounded
  by the creak and shuffle of shifting structures. All eyes were on the
  Monitor as he continued. 'You have already guessed - our Numbers were
  holding the Second Law of Thermodynamics at bay. The universe is a closed
  system. In any closed system entropy is bound to grow until it fills
  everything. The deadly secret, unknown until now beyond the bounds of
  Logopolis, is this . . .' The Monitor's voice trembled, and they had to
  strain to hear his next few words. 'The fact is, the universe long ago
  passed the point of total collapse.'
  For a moment Adric didn't take it in. The Second Law of Thermodynamics
  predicted that any system would eventually end in 'heat death', overwhelmed
  by the entropy it had produced. But how could the universe have passed the
  point?
  'We had the means to postpone the time,' the Monitor was saying, as if in
  reply to the boy's unspoken question. 'The only way was to dispose of
  entropy. The universe was closed, so we opened the system by creating voids
  into other universes.'
  'The Charged Vacuum Emboitement!' the Doctor exclaimed. 'We passed through
  one of your voids, Monitor.' He glanced at Adric. If it hadn't been for an
  accidental encounter with a CVE, the Doctor and his TARDIS would never have
  wandered into the small universe where he had met the boy. 'We thought the
  CVE was a natural phenomenon.'
  'I wish it were,' said the Monitor. 'Then there would be no need for them
  to be sustained by the energies of Logopolis.'
  Suddenly Tegan understood the inhuman dedication of all those rows and rows
  of Logopolitans. So this was what had been driving them on: the fact that
  
  they and they alone were capable of keeping the whole universe going long
  after it ought to have ground to a halt.
  'But without those energies,' the Monitor continued, 'the Charged Vacuum
  Emboitements will be closing now. It depended on our continual endeavours -
  a temporary solution while the Advanced Research Unit worked on a more
  permanent plan. But nothing will come of that now.'
  There was silence for a moment. Then the Master, who had been thinking
  furiously said, 'What Research Unit?'
  'A team devoted to discovering a stable solution that did not depend on our
  own continued efforts. But now the team is destroyed. To think of that work
  too going to waste . . .'
  'There must be something we can do,' Tegan interrupted loudly. She turned
  to the Master and shouted, 'This will teach you to meddle with things you
  don't understand.' And then she wished she hadn't. The rocks above their
  heads, weakened to the consistency of pink sugar, began to cascade down,
  thundering into the street. She felt her arm grabbed, and then they were
  all running - where, she couldn't see for the dust and the Doctor's scarf
  blowing across her face.
  They stopped, and she looked back to where they had been standing. The
  street was now a flat gully, still filling with silt that hissed down from
  the mounds of crumbling rock on either side. 'What did I do?' said Tegan.
  'Your loud mouth,' Adric whispered.
  'We are beyond recriminations now,' sighed the Monitor. 'Beyond everything
  . . .'
  'Almost everything.' The Doctor's voice was even and controlled. He turned
  to the Master. 'I can see only one possible course. As Time Lords you and I
  have a special responsibility.'
  'No,' the Master replied immediately, as though he had been anticipating
  the suggestion. 'I refuse to contact Gallifrey.'
  'I'm not very keen on the idea myself. But I was going to suggest we pool
  our resources.'
  The Master pondered the thought for a moment. 'If we do that there will be
  no question of your returning to Gallifrey. Perhaps for ever.'
  'I'm happy to leave that problem for the future,' said the Doctor. 'If
  there is one.'
  Nyssa's jaw tightened as the Doctor extended his hand to the Master. But it
  was Tegan who spoke first. 'Doctor! What are you doing?'
  'How can you!' Nyssa exclaimed. 'The creature who killed my father . . .'
  The Master remained still, savouring the moment. Then he raised his own
  black-gloved hand and moved towards the Doctor. 'Together, then.'
  It was then that the Doctor looked round, very much sensing the hostility
  of his companions. He began gently at first: 'I can't choose the company I
  keep. Not in these circumstances. In fact I have never chosen my own
  company.' He pointed at Nyssa, his voice a little harsher now. 'You
  contacted me, you begged me to help you find your father.' Then his eyes
  shifted to Tegan. 'And you, Tegan, your own curiosity brought you into this
  . . .' His tone was positively harsh as he turned to Adric. 'As for you,
  boy, what are you? A stowaway!'
  Adric realised that the Doctor was doing this to make their separation from
  him easier to bear, but it was painful nevertheless to be reminded that he
  had forced his company upon the man he so admired. And it was even more
  painful to see the Doctor turn his back on his companions and reach out
  towards the evil black hand of this being who was his sworn enemy.
  'Together,' said the Doctor, looking hard into the Master's face. 'The one
  last hope.'
  'For all of us,' the Master acknowledged.
  Solemnly the two Time Lords shook hands.
  
  10.
  'Now . . . I want no arguments from any of you. Adric, Tegan and Nyssa . .
  . that way!'
  The rocks which had once formed high cliffs around them had now crumbled
  down to a landscape of gentle undulations; a pink plain lay where the great
  whispering City had once stood. Beyond the Doctor's gesturing arm they saw
  only the distant outline of the Central Register, surmounted by the wire
  basket of the antenna, broke the skyline. But his finger was pointing to a
  small rectangle some way ahead.
  'The TARDIS!' exclaimed Nyssa.
  Tegan peered at the distant blue shape. 'It's followed us!'
  'But how can it do that,' asked Adric, 'with no one in it?'
  'Did I say there was no one in it?' snapped the Doctor.
  The two Time Lords stood shoulder to shoulder. The crisp, imperative tone
  of the Doctor, and something about the evil certainty of the Master's
  smile, persuaded them of the uselessness of pleading to stay. The Doctor
  was collaborating with the Master, and there was no place for them now in
  his plans.
  He waved them off with an irritated flap of his arm. 'My friend will take
  care of you.'
  The three companions trudged towards the TARDIS, speculating about who this
  'friend' might be. Nyssa guessed it must be the man who had brought her to
  Logopolis.
  She was right. They saw the translucent figure standing at the door, but he
  had slipped inside before they were close enough to make out his features.
  It was not until much later, when the TARDIS was in flight, that they were
  to meet him face to face.
  With a sense of relief the Doctor watched them enter the TARDIS, aware of
  the evil presence at his elbow. At least there was a chance they would be
  
  safe. Then he became aware that the Monitor was nowhere to be seen.
  'The fool has deserted us!' said the Master. 'Doesn't he realise he has no
  chance of survival without our help?'
  Desertion didn't sound like the Monitor's style at all, the Doctor pointed
  out. He had gone somewhere for a purpose.
  'Purpose!' exclaimed the Master. 'A word almost without meaning now. If
  he's trying to salvage the Research Team's work he may have gone back to
  the Central Register.' The Master shaded his eyes and peered towards the
  distant building. Parts of it had been eroded already, but it seemed to be
  standing stronger than the rocks around it. It occurred to the Doctor that
  this might be because of its relative newness. But there was no telling how
  long it would last.
  Together the Doctor and the Master began to pick their way towards it
  through the debris. Occasional small landslips opened up beneath their
  feet, impeding their journey, and reminding them of the increasing
  instability. Soon even this dusty ground would become unstable. And more
  was at stake than just Logopolis. Even as they advanced painfully towards
  the Central Register, the rot was spreading outwards through the universe,
  the Second Law of Thermodynamics unleashed after aeons of constraint.
  'I suggest we collect the Monitor, then get out,' said the Doctor.
  'How? In my TARDIS?'
  'There's no other way.'
  The Master smiled. 'You're presuming a lot, Doctor.'
  'Aren't I?' said the Doctor. 'And on so short a friendship.'
  By the time the two Time Lords had reached the steps of the Central
  Register the TARDIS was parsecs away. But the dematerialisation had not
  gone quite according to the Doctor's plans. The light was already flashing,
  ready for departure from Logopolis, when the door suddenly opened and Tegan
  backed out, her flight bag over her shoulder.
  'Come back!' It was Adric calling from inside. 'None of us wants to leave
  the Doctor. But it's best to do as he says.' He appeared at the door,
  pleading with Tegan.
  'Best for him, maybe. It's not personal devotion, I can tell you that. But
  he's guaranteed to get me back to London Airport, and I'm going to stick
  with him to make sure he keeps his word.' And she set off resolutely back
  the way they had come.
  'Tegan!' But it was no good just calling her name, and he couldn't run
  after her and leave Nyssa. The TARDIS was already beginning to chuff and
  whirr. Adric closed the door . . . and the TARDIS was gone.
  Tegan found the spot where the Doctor and the Master had been standing, but
  the only sign of them was a set of vague footprints. At first it seemed an
  easy track for someone brought up in the outback to follow, but small
  potholes kept appearing, and the wind blew streaming veils of dust across
  the ground, obscuring the horizon.
  She was entering what once must have been the middle of the City, if what
  remained of the dwellings was anything to go by. The ruins were taller
  here: cells open to the sky, some of them almost complete except for their
  roofs. The ground was more solid, but in a way that made it more dangerous.
  Instead of shifting sand beneath her feet, great crevasses would
  occasionally open up just where she was about to step.
  Should she have stayed in the TARDIS, she wondered. That was the trouble
  with having an independent mind. Tegan consoled herself with the thought
  that if being lost and frightened on a rapidly disintegrating planet was
  good for the moral fibre, hers must be receiving a tremendous boost.
  The Central Register was still recognisable, although portions of the
  ceiling and walls had crumbled away, letting in the opalescent light of the
  
  Logopolitan sky. The two Time Lords found the Monitor where they expected,
  seated at the Earth computer surrounded by sheets of print-out. Several of
  the large disk-drive units that surrounded the console were humming with
  activity.
  The Doctor touched the Monitor's arm. 'The stability is now critical. You
  must come with us.'
  'For precisely that reason I must stay here, Doctor.'
  'What can you do here?' said the Master. 'You told us Logopolitan maths
  wouldn't run on a computer.'
  The Monitor gestured to the print-out strewn across the desk in front of
  him. 'We were developing this as the program to take the burden from our
  own shoulders: a series of data statements to keep the Charged Vacuum
  Emboitements open of their own accord.'
  'The Advanced Research Project?' asked the Doctor.
  The Monitor nodded. 'The computer holds a complete log of that research.'
  The Master snatched at the print-out. Somewhere in all this carefully
  annotated mass of numbers there might be a permanent solution to the
  problem of keeping the CVEs open. While the Monitor continued his
  preoccupation with the console, the Master and the Doctor poured over the
  document, tracing and retracing the folds of logic.
  Eventually, the Master left the document and went to peer over the
  Monitor's shoulder. It had become clear to the Doctor, who paused now to
  suck the end of his scarf and think, that although the work of the Research
  Team was far from complete, it had certainly been on the right track.
  The Master felt differently. He returned to whisper into the Doctor's ear,
  'His work is loose, speculative, useless. We cannot wait for him. We must
  vacate.'
  A creaking sound, emanating from the walls, reminded them that the local
  structure would not hold much longer. 'Vacate?' echoed the Doctor. 'Where
  to? The collapse will spread out like ripples in a pool throughout the
  whole of space-time. No, what we have to do is . . .' He tailed off into
  silence, somewhat stuck for options.
  'Well, Doctor?'
  The Doctor waved his arms vaguely but enthusiastically. 'A positive
  response. Something definite, resourceful. Entropy works by rusting the
  resolve quite as much as by crushing cities into sand dunes.'
  'You have a concrete idea behind all that poetry, Doctor?' sneered the
  Master.
  The Doctor had to admit he hadn't. He put his hands back in his pockets and
  returned to his study of the print-out.
  'My dear Doctor. You're a poor scientist. It's easy to see why you make so
  many mistakes.'
  'And why you make so few friends,' the Doctor replied.
  The bitter exchange was interrupted by the Monitor rising from the Earth
  computer. 'I have done what I can in the time. A desperate last effort. It
  only remains to align the antenna and beam the program out to space.'
  The antenna still held firm on what remained of the roof. It was a doubtful
  enterprise; even the Doctor for all his optimism had to admit that. He was
  about to follow the Monitor through the narrow door that lead to the upper
  storey, when, through a gaping hole in the wall, he saw a familiar purple
  uniform in the street below. 'Tegan!' shouted the Doctor.
  'Thank heavens you're still here, anyway.' She arrived breathless at the
  top of the steps, her uniform dusty and her shoes scuffed.
  'Tegan! I told you to get out of here.'
  'No thanks, Doc. I'm staying with you. You're the only insurance policy
  I've got.'
  The Doctor dragged her inside, ducking a shower of debris. Above them,
  through ever increasing gaps in the ceiling, they could see the Monitor
  treading warily across the roof towards the antenna. At one point he
  stopped to wave to them. 'There is a CVE close by we might be able to re-
  
  open, he called down, pointing to an area of sky.
  Tegan held her breath; his progress across the crumbling roof looked
  suicidal. 'What's he doing?'
  The Master snorted by way of answer. 'He can do as he pleases - he's
  harmless. But you and I, Doctor, we must form a plan. I propose . . . one:
  withdrawal to a position of temporary security; two: reconfiguration of our
  two TARDISes into time cone inverters; three: creating a stable safe zone
  by applying temporal inversion isometry to as much of space-time as we can
  isolate . . .'
  Tegan had been unable to take her eyes off the Monitor, and now her scream
  interrupted the Master. He and the Doctor turned to look upwards. Another
  shower of silt was pouring from the ceiling, caused by loose stonework
  tumbling from the roof where the Monitor was flailing, as if trying to
  retain his balance. And then, as if in slow motion, they saw him slip. But
  the horror of it was that instead of falling heavily, the figure of the
  Monitor began to float down through the ceiling towards them, like some
  huge flake of ash blown in the smoke of a fire.
  The body hit the floor with scarcely a sound, cracked open like a hollow
  shell, and powdered away to dust.
  Tegan stared at the spot, her hand pressed involuntarily against her mouth.
  'Horrible, horrible.' She heard a harsh, dry voice that seemed to speak her
  thoughts and looked up to see the Master backing away towards the door.
  'Hardly more horrible than turning people into shrunken dolls,' she shouted
  at him.
  The Master's eyes were wild and staring in his pallid face. 'No! Anything
  but that. Do what you like, Doctor. Logopolis is yours!' At the door he
  turned and ran, disappearing down the stairs with debris cascading after
  him.
  'Doctor! We must stop him!' She ran to the window overlooking the street.
  'The Master's getting away.
  The Doctor had said nothing for a long time. Now he spoke slowly, as if all
  sense of urgency had drained from him. 'Which means we can't - as he's got
  the only TARDIS left on Logopolis.'
  'Then we've got to get after him.' She ran to the Doctor, but he gestured
  to her to let him think for a moment.
  'Reconfigure the two TARDISes into time cone inverters,' muttered the
  Doctor, pensively echoing the Master's proposal. 'Yes, it would have worked
  - for at least part of the universe. What a waste of a brilliant mind.'
  A slab of plaster exploded into fragments at Tegan's feet. 'And a waste of
  two more brilliant minds if we don't do something soon.'
  'You're right. The Monitor's program to re-open the CVE . . . There's a
  slight chance . . .' The Doctor's movement towards the Earth computer
  opened up a rift in the floor, cracking the console. The disk drives
  juddered to a halt. 'Correction - there was a slight chance.'
  The Doctor fell to musing again, infuriating Tegan, who put her lips to his
  ear and said loudly, as if she were talking to a deaf old man, 'Come on,
  Doctor. We've got to stop the Master from taking off.'
  The Time Lord raised an eyebrow. 'Why? There's no point in running from
  place to place without a positive approach to take with us. The solution is
  here . . . somehow . . . Or somewhere very like this. I had a strange
  feeling we were very close - before this!' He tapped the Earth computer
  emphatically; a panel split and clattered to the floor. The Doctor knelt
  down, absent-mindedly inspecting the damage. 'I sympathise,' he said,
  patting the machine. 'I've never felt so close to dissolution before.'
  Dissolution? The word sounded so final to Tegan. 'This can't really be the
  end, Doctor. It can't be.'
  The Doctor smiled up at her, as if only then reminded of her presence. 'Of
  course it can't. There must be something we can do. Some desperate, remote
  chance. Remote!' He paused to savour this last word, as if there might be
  the flavour of salvation in it.
  
  'If it's remote it won't be here, will it, you stupid . . . Doctor!'
  Tegan's voice betrayed her panic, but it came out as anger.
  The Doctor's eyes flashed back in reply. He clapped his hands together. 'Of
  course! Here but not here! That's it.' He suddenly turned on what remained
  of the computer, and began tearing it to pieces with his hands.
  'Doctor! What are you doing?'
  'An experiment in optimism. Come on, you can help. I want this thing in
  pieces.'
  Utterly baffled, Tegan threw herself down beside him and helped him tear
  away the brittle casing.
  It seemed to take forever. There were several layers; some could be torn
  out like damp cardboard, while others were solid and had to be eased out
  with the Doctor's sonic screwdriver. By the time the interior lay exposed
  her hands were raw from the effort.
  The Doctor said little during the work, and when she had asked him three
  times what on Earth he meant by 'here and not here' all he said was:
  'Precisely - on Earth.' And then he went very quiet, rolled back the
  voluminous sleeves of his coat and reached into the wreckage.
  The thing he eased out was a long rectangle the colour of emerald, to which
  was attached a neat pattern of small objects that looked like large flat
  beetles with silver legs. Tegan recognised them as some sort of electronic
  component.
  The Doctor turned the board over in his hand, inspecting it carefully. 'As
  I thought . . . Bubble memory.' He handed the device to Tegan with a broad
  smile. 'Bubble memory . . . You realise what this means?'
  'No, as a matter of fact I don't, Doctor.'
  The Doctor reached into the machine again, and produced several more of the
  flat boards, passing each one carefully over to Tegan. 'Bubble memory is
  non-volatile. Remove the power - and the bit-patterns are still retained in
  tiny magnetic domains in these chips.'
  So that was the Doctor's idea! The Research Team's last program was still
  here, in the pile of memory boards Tegan held in her hands. 'Which would be
  great if we had a computer to run it on,' she said.
  'But there is! Exactly like this one.' The Doctor grinned as the light
  began to dawn in her eyes. 'On Earth, as you suggested.'
  'The Pharos Project!' Tegan exclaimed.
  'Exactly,' said the Doctor. 'Now all we have to do . . . is get there.'
  11.
  
  'Master! Wait! There may be one last chance. Master!'
  The Doctor's voice was hoarse with calling. Tegan took her turn, giving her
  loud Aussie voice full rein. 'Master! Don't take off. Please . . . The Doc
  thinks he's got the answer.'
  Inwardly Tegan was close to despair. Screwing up their eyes against the
  gusts of fine pink dust, she and the Doctor had trudged out from the ruins
  of the Central Register in a wide sweep of the flattened landscape. It
  seemed to her that even if there were something in the Doctor's crazy plan
  for the fragile memory boards she was carrying, the chances were that the
  Master was long gone.
  But the dismal wasted world of Logopolis presented the Doctor's sometimes
  facile optimism with one small ray of hope. He thought - though the
  calculations to confirm his theory would have taken several days - that a
  dematerialising TARDIS would have to create a major disturbance to the
  unstable landscape, something they were bound to notice. Apart from the
  constant cracking and shifting of the ground beneath their feet there had
  been nothing on that scale since the landslide Tegan had caused. If the
  Doctor's guess was right, the Master was still on Logopolis!
  On the basis of this long shot they were trekking the dangerous territory,
  hoping to run into the man the Doctor hated most in the whole universe.
  Tegan's dark doubts grew with every precarious ruin they explored. But she
  was the one who found the glove.
  'Doctor! Over here!' She knelt and peered at the shiny black object. It was
  lying palm up, partly covered by a mound of pink dust that had piled up
  around the base of a flat fluted pillar lying horizontally along the back
  of the cell.
  The Doctor seemed a long time coming; perhaps he had missed the cave. With
  the idea of going to the entrance to call again, she reached out to pick up
  the glove.
  The black leather fingers closed tightly around her hand.
  The Doctor heard Tegan's screams and arrived at a stumbling trot. In
  struggling to escape she had pulled the hand out of the ground, revealing a
  flailing length of arm. She was also in danger of bringing down what
  remained of the roof. The Doctor clapped one hand firmly over her mouth and
  grabbing the disembodied arm with the other heaved backwards with all his
  strength.
  The Master's face emerged from the sand beneath the pillar. 'Just in time,
  Doctor,' he said, spitting out dust. 'I have almost had my fill of
  Logopolis.'
  The Master had stumbled through a multitude of ruins before finding the fat
  fluted column jammed tightly into one corner of the cell, supporting the
  sagging roof. In the geological upheaval it had shifted too close to the
  wall for him to be able to open the door.
  At first he had tugged at it impatiently, and then with violence. Powdered
  rock plummeted from the roof, the pillar teetered and then crashed down
  towards him, bringing with it a fresh cascade of rubble. The settling dust
  had brought an uneasy silence to the cell. Trapped under the immense weight
  of his own TARDIS there was nothing to do but wait.
  Patience had brought its reward. Scrabbling with their hands at the loose
  ground Tegan and the Doctor finally managed to prise the Master from under
  the pillar and pull him to his feet.
  The Master dusted himself down as best he could. 'I'm grateful, Doctor.'
  'Splendid,' said the Doctor, 'because now it's your turn to help us.' He
  glanced down at the pillar, and noticed that the door, normally concealed
  by the fluting, had come ajar, hinting at the inky vastness of the
  interior. As the three of them hauled the column upright, the Doctor added,
  'One good lift deserves another, don't you think? Next stop Earth.'
  
  Adric had come to think of him as 'the Watcher', this strange friend of the
  Doctor's who came and went like pictures in the fire, and never spoke. The
  Watcher seemed to prefer solitude; now he wasn't even allowing them to
  share the console room with him. It reminded Adric of the time the Doctor
  had put him outside the door while he answered the cloister bell, except
  that now instead of Milton, Adric had Nyssa to share the corridor with him.
  'But the Doctor usually lets me help him.' The boy's protest went unheeded
  and the door closed.
  'I don't think he needs our help,' Nyssa said. 'He seems to know what he's
  doing.' When he had fetched her from Traken he hadn't said anything, just
  beckoned. But there was something oddly familiar about the strange figure
  that had stopped her feeling afraid. He seemed very like the Doctor in many
  ways, but so solemn, as if he carried all the troubles of the world on his
  shoulders. 'It's as if he was watching over me,' Nyssa said.
  So Nyssa had that same feeling! Adric told her about the name he had
  privately given him. 'I'm not afraid of the Watcher either,' the boy added.
  'But I would like to know who he is.'
  Adric slowly turned the handle to peep into the console room. Through the
  narrow crack in the door he could see the Watcher's hands drifting over the
  console controls. 'He's setting the co-ordinates . . . no, he's . . .'
  Adric had to stand on tiptoe to see better.
  Nyssa hadn't approved of the idea of spying on the Watcher, but now she
  said impatiently, 'Well? What is he doing?'
  Adric caught his breath. 'He's unsetting the co-ordinates! He's
  disconnecting the co-ordinate sub-system . . . But he can't do that. Not in
  mid-flight!'
  'What is it? What's the matter?'
  The boy slammed the door shut, and by way of answer to Nyssa's question
  grabbed her and threw her roughly to the floor. At the same moment the
  TARDIS rocked violently. For several sickening oscillations the two
  companions rolled back and forth across the pitching corridor. Then, as the
  movement stabilised, the solid walls around them appeared to melt and glow,
  and everything within vision began to merge into a single featureless field
  of brilliant white. A roaring sound filled the corridor. Over it Adric
  heard Nyssa's voice. 'Adric? What's happening?'
  He had to shout to be heard above the mounting noise. 'It's the Watcher.
  He's taking us out of time and space altogether!'
  Adric remained conscious, but for a long time he seemed to hover on the
  very edge of existence, like a thought in search of a mind to think it.
  From time to time he caught the sound of Nyssa's voice amidst the rush and
  roar that filled his head, but the words were indistinct and may have been
  in his imagination, or perhaps in hers. His mind brimmed over with the
  whiteness that had no boundary in space or time. And then, slowly at first,
  the shapes came back. The twisting line where one corridor wall met the
  floor, the horizontal plane of the door, the perfect circles of the
  roundels inlaid into the panels, appeared one by one like fresh pencil-
  marks on blank paper. Eventually the roaring died, leaving them in a
  silent, airy brightness that was unmistakably the TARDIS corridor, but
  somehow infinitely more spacious between its insubstantial bounds.
  Nyssa was sitting beside him on the floor, 'Is that where we are?' she
  asked, as though nothing had interrupted the conversation. 'Outside space
  and time?'
  'Yes,' said Adric. 'And hovering. The TARDIS isn't supposed to do that.'
  Nyssa stood up. 'We seem to be safe.'
  Adric scrambled to his feet beside her. 'Safe, yes. That's the point, I
  suppose. The Doctor's told the Watcher to look after us.'
  'I'd rather be with the Doctor,' said Nyssa.
  'Me too,' Adric said. 'What are we going to do?' The boy knew, even as he
  asked, that it was an empty question. Guided by the Watcher, the TARDIS had
  
  made the only possible escape from the deadly collapse that was spreading
  out from Logopolis. But the Doctor was in the middle of it, and now there
  was nothing they could do to help.
  Nyssa's reply was calm and practical. 'Well, if the Watcher won't let us in
  the console room, you'd better show me round the rest of the TARDIS.'
  The technician reached out for the paper cup that stood somewhat
  incongruously in front of the high-technology switches and LED indicators
  of the computer console. He had been trying to crack the problem since
  starting his six o'clock shift that evening, and here he was on the other
  side of midnight and range errors of two of the global variables were still
  slipping through the compiler. That was typical of the Pharos Project -
  month after month of no data coming in from the antenna meant you filled in
  the time chasing petty errors out of the software until your eyes popped.
  The moment he lifted the paper cup he realised it was empty. The strains of
  Tchaikovsky's 'Nutcracker Suite' pouring into his ears through the
  lightweight headphones were no substitute, coffee was what he needed. He
  got up, stowing the cassette recorder into the pocket of his white lab
  coat, and, crushing the cup and lobbing it expertly into the wastepaper
  basket, went out into the corridor to wring fresh inspiration from the
  beverage dispenser.
  The Pharos Project computer room was illuminated by a single lighting bar
  over the console, which left pools of shadow in the remoter areas where the
  tape and disk drives hummed on stand-by. No sooner had the technician moved
  out into the corridor than a new voice joined the gentle chorus: a kind of
  chugging noise emanating from a rapidly thickening patch of yellow that
  stained the gloom in one corner. The shape congealed into a stubby pillar,
  Ionic in proportion, but with a leafy capital and base reminiscent of the
  Corinthian order. A door, not a usual feature of its Ancient Greek
  antecedents, opened up on one side, and the Master stepped into the room.
  'You see,' he said quietly to the Doctor, who followed him, 'we have
  materialised exactly on the co-ordinates.'
  'Spot on,' the Doctor conceded. 'I envy you your TARDIS, Master.'
  'Excellent, Doctor. You're improving. Envy is the beginning of all true
  greatness.'
  Tegan followed the two Time Lords out of the TARDIS, and found herself in a
  room so like the Monitor's Central Register, as it was before the disaster,
  that at first she thought the destruction of Logopolis had only been a bad
  dream. And then from the corridor she heard the jingle of coins in the
  automat; unmistakably an Earth sound.
  The Doctor pulled her back against the wall. The Master was on the other
  side of the door when the technician came back into the room, sipping at
  his coffee. As the door swung shut behind him, Tegan saw the Master taking
  an unpleasant-looking piece of technology from his coat. He seemed to be
  levelling it at the technician.
  The Doctor was beside him in an instant. 'No!' he said in a fierce whisper,
  pulling the Master down behind a disk drive cabinet.
  The Master calmly handed the device over to the Doctor. 'The light speed
  overdrive from my TARDIS. You'll need it for transmission.' His eyes
  twinkled with a mockery of innocence.
  'I'm sorry,' said the Doctor. 'I thought . . . '
  'That I would kill him, Doctor? Why should I, when you have the time and
  patience to explain our presence to this gentleman.' There was no mistaking
  the sarcasm in the Master's voice.
  'Yes, well . . . I can try.'
  Signalling to Tegan to get the memory boards from the Master's TARDIS the
  Doctor stood up. The technician was totally immersed in his music and his
  computations; it was certainly going to be awkward, the Doctor realised, to
  announce their presence without frightening the life out of him.
  
  Such humane considerations were no hindrance to the Master, crouched behind
  the cabinet. Unfortunately for his plans he had just aligned the re-
  dimensioner on the precise site of the posterior cerebellar notch at the
  back of the technician's skull when Tegan re-emerged from the TARDIS with
  the printed circuit boards. Instinctively she cried out.
  The Doctor's head swivelled round immediately, and at the same time the
  weapon flashed in the Master's hand. But before the energy beam had time to
  arrive at its target the Doctor had dived at the technician, sending him
  skimming across the room on the casters of his chair.
  The Doctor turned his fury on the Master. 'There must be no more deaths!'
  'Never mind. You've solved our problem, Doctor.' He jerked a thumb towards
  where the technician lay, a crumpled unconscious heap against the wall. The
  Master ripped off the headphones and dropped them into the wastepaper
  basket while the Doctor checked the man's pulse and made him comfortable on
  the floor.
  'I feel we've been spared a very difficult conversation,' said the Master.
  Then he turned to Tegan, snapping his fingers. 'Come along, now. Door . . .
  blinds . . . lights. If this interesting scheme is to work, there's a great
  deal to be done before dawn.'
  Giving much thought to the task they were about to embark upon, the Doctor
  absent-mindedly stirred the technician's coffee with a pencil and raised it
  to his lips.
  Despite the confusing new spaciousness of the corridors, Adric had managed
  to find the TARDIS cloister room again. He walked round the perimeter with
  Nyssa, pointing out the crumbling stonework that had started off the Doctor
  on his resolve to repair his ship. It looked particularly shoddy in the
  over-lit brilliance induced by timelessness and spacelessness.
  'Things in the TARDIS often stop working for no reason,' the boy said. 'The
  Doctor's very good at coping with it, but it's a terrific strain on him.'
  'Entropy again,' Nyssa said. 'You can't get away from it.'
  Adric stopped suddenly, looking across to the other side of the cloisters.
  A white shape was visible through the foliage, pacing restlessly backwards
  and forwards much as the Doctor had done the day Adric had first discovered
  the cloister room.
  'It's uncanny! From here . . . it might almost be the Doctor.'
  The echo of Adric's whispered remark to Nyssa must have carried around the
  wall to the other side of the cloisters, because at that moment the Watcher
  stopped pacing and looked in the direction of the two companions. And
  exactly as the Doctor had done before, the Watcher took a pace forward and
  beckoned to Adric across the quad.
  Nyssa wanted to hear all about what the Watcher had said, but explanations
  had to wait while Adric hurried her through the white brilliance of the
  corridors and back to the console room.
  'Are we travelling again?' Nyssa asked, closing the door behind her.
  'We have to log in the co-ordinate sub-systems first.' Adric waited until
  the row of yellow lights were all glowing above the set of initiation
  switches. Then he unlocked the sub-system panel, as he had seen the Doctor
  do so many times before.
  'He actually spoke to you?' asked Nyssa.
  'Yes, of course,' said Adric, smoothing out the piece of paper the Watcher
  had given him. He hesitated. 'At least . . . yes, he must have spoken to
  me.' He had the distinct impression that it had been a conversation, but
  when he tried to remember what the Watcher's voice was like he could only
  hear the Doctor speaking.
  'We're going back into space and time?' asked Nyssa, looking over Adric's
  shoulder at the writing on the paper. 'What changed his mind?'
  
  'It didn't change,' Adric told her, surprised at his own confidence. It was
  impossible for him to know the Watcher's thoughts, and yet he felt sure
  their new companion was in some way part of the future. His mind hadn't
  changed because he knew - he had always known - what was going to happen.
  Nyssa wanted to be shown how the TARDIS worked, but unlike Tegan her
  scientifically trained mind was not to be thrown into confusion by long
  words. Adric explained as much as he knew, but had to confess that most of
  the theory was too complicated even for his mathematical brain.
  Luckily the Watcher had told him exactly what to do. According to the piece
  of paper, Earth was in sector eighty twenty-five of the third quadrant.
  'The temporal settings are laid in on this panel . . .' Adric told her. 'It
  always looks so easy when the Doctor does it.'
  'But where are we going?'
  'The Pharos Project. Now just leave me alone for a bit. I have to do some
  calculations.'
  Adric settled in front of a small keyboard set into the console. Nyssa
  turned to the viewer screen, and saw a starfield, a million glittering
  diamonds scattered across a cushion of black velvet. From outside space and
  time she was looking down on an image of the whole universe.
  Adric finished his calculations and came to stand beside her. Curved lines
  like meteorological isobars were inching across the screen, and as they
  advanced, the stars they covered dimmed and died. It was as though some
  black ink blot were spreading across the universe, indelibly staining out
  the light.
  Nyssa pointed to the awesome blackness of the encroaching blot. 'Look at
  the entropy field. It's huge now.' Then a thought occurred to her. 'Is
  Earth on this star map?'
  Adric pursed his lips for a moment, then indicated the edge of the map
  furthest from the invading darkness. 'This is Earth's galaxy. Somewhere
  here. The Earth people have a few hours left.'
  'And Traken?' asked Nyssa.
  The question took Adric by surprise. He waved his finger vaguely around the
  middle of the screen and said, 'Traken should be . . . Traken's . . .' And
  then he realised that it lay directly under the spreading dark stain of
  entropy.
  'That's funny,' said Nyssa. 'I can't even see Mettula Orionsis . . .' And
  then she tailed off as she saw Adric's face.
  'I'm sorry, Nyssa . . . I'll switch it off.'
  She stopped him as he was reaching for the switch. 'No! Wait!' She wanted
  to look a little longer, giving herself time to absorb the knowledge that
  the death of her father had been followed by the destruction of her whole
  world. She had never hated the Master so much as she did at that moment.
  'He killed my step-mother, and then my father . . . and now this! The world
  I grew up in - blotted out forever!'
  Adric took hold of her hands. She looked at him for a moment, her eyes wet
  with tears. Then gently releasing herself from him she reached out and
  flicked off the viewer.
       A moment later the time column juddered into life, and the lighting
  began to whiten again, bleaching out the shapes around them. 'Hold on,'
  said Adric. 'We're going back now.'
  The two companions gripped the console for support as the room filled with
  the roaring noise that announced the beginning of their re-entry into space
  and time.
  
  12.
  Tegan helped the Doctor and the Master unscrew the side of the computer
  cabinet, then she left them with the memory boards and peeped out into the
  corridor. The echoing darkness hummed faintly with the sound of distant
  machinery as she tiptoed to a window at the end and pulled down a slat of
  the Venetian blinds. They were on the second floor of a building that
  looked down onto a fenced-off area. In the light of the high yellow lamps
  slung between tall poles below, the long low huts looked like a tangle of
  barges moored in the black asphalt. Beyond the huts the high wire fencing
  was interrupted by a main gate, approached by a wide open space. Tegan
  deduced from the white markings that it was partially a car park. Over it
  all a huge skeletal structure rose up into the night sky like the Eiffel
  Tower; but instead of coming to a point it bloomed into the familiar shape
  of a vast metal bowl. The Pharos antenna, she thought. The original of the
  one on Logopolis.
  The two Time Lords worked on through the night, and Tegan kept returning to
  the window, until the dark horizon began to sharpen with an edge of silver.
  'The dawn's coming up,' she whispered, coming back into the computer room.
  'And they've got security guards out there.' She had noticed dark shapes
  moving by the main gate.
  The collaboration between the two Time Lords was not going entirely
  smoothly. At the Doctor's signal the Master prodded the console keyboard
  again. 'It's still not running. The program is useless.'
  'The Monitor gave his life trying to complete it,' the Doctor replied
  sharply. 'We must try to do him justice.'
  'Indeed? And what makes you so sure this is going to work?'
  The Doctor smiled pleasantly and took over the keyboard. 'While there's
  
  life, it's six of one and half a dozen of the other.'
  'Woolly thinking, Doctor,' sneered the Master.
  'Very comforting, when worn next to the skin.'
  The keyboard clattered under the Doctor's fingers for a moment or two. The
  Master leaned over to inspect the screen, which had begun to fill with
  figures. 'It's running,' he said, a note of surprise in his voice. 'If you
  can call this alien gibberish a program.'
  'We'll know once we've managed to download it onto the antenna. Now, in
  view of the guards out there - or rather, to avoid being in view of the
  guards - I suggest we pop across in your TARDIS.'
  The Master tapped the light speed overdrive, which was sticking out of the
  Doctor's top pocket. 'Not unless we deplete this, and we'll need it for
  transmission.'
  The Doctor eyed him suspiciously. 'Are you sure?'
  'Of course I'm sure. The mean free path would be reduced to a matter of
  millimetres. It can't be done, Doctor.' Mockingly he added, 'Not even with
  faith and hope.'
  The Doctor glanced at the door. 'All right, we'll risk the guards. But
  we'll have to be careful.'
  The TARDIS carrying Adric and Nyssa had arrived at its destination, and
  materialised discreetly in the shadows around the base of the Pharos
  antenna. Inside, the two companions had been watching the huge basket-like
  structure on the viewer screen.
  'So that's what the Earth people are using to beam messages to the stars,'
  said Nyssa. 'Trying to call up alien intelligences.'
  'Then they should be very pleased to see us,' Adric said, pulling the door-
  release lever. 'Except that they won't be.' The sound of dawn birdsong
  filtered in as the big double door swung inwards.
  'Why not?' Nyssa asked.
  'People never are when they get what they've always wanted,' Adric replied.
  'You'll see.'
  Together they stepped cautiously out into the cold morning air and ran for
  cover.
  At the end of the corridor the Doctor paused to lift a slat of the venetian
  blinds. Tucked into the shadows on the far side of the car park, he saw the
  unmistakable blue shape of the TARDIS.
  The double doors were ajar, and in the opening loomed the vague outline of
  the figure that had followed him to Logopolis and back. Something
  distinctly proprietorial about the patient way he waited in the TARDIS
  entrance sent a chill through the Doctor's body.
  'Hey, Doc, are you OK?' Tegan was by his side, recalling him to the
  business in hand.
  The Doctor turned from the window, instantly himself again. He knew the
  danger of showing any sign of weakness in front of the Master. 'This is
  going to need split-second timing,' he said crisply. 'We've got to get
  across to the antenna control room and re-align it on whatever's left of
  Logopolis. That way we should be near enough to that CVE the Monitor was
  trying to re-open.
  The Master confirmed the plan with a nod.
  'Good,' said the Doctor. 'Then follow me. And watch out for those security
  guards.'
  Downstairs the sonic screwdriver made quick work of the chain on the safety
  door that lead out into the enclosure, and from there it was a short sprint
  across open ground to the cover of the row of huts. They pressed themselves
  up against the wall while a group of early morning workmen wheeled their
  bicycles in through the main gate and ambled past within a few feet from
  
  where they stood. The Doctor contemplated the open ground between them and
  the antenna, mounted on its cluster of girders and gantries. The sky was
  getting lighter, and every delay made the venture more dangerous.
  Just as he judged it right to move, two security men pulled open the main
  gate, allowing a car to roll slowly in towards the Doctor and his party,
  cutting off their direct route to the antenna.
  The Doctor pulled Tegan back into the shadow of the huts, but behind them
  the Master, tiring of the delay, reached into his coat for the weapon he
  had intended to use on the technician.
  The Doctor noticed the movement, and turned in time to grab the weapon just
  as it was about to go off. But the noise of the scuffle alerted the two
  security men, and a voice shouted, 'Intruders! Come on, after them!'
  The Doctor broke cover, and Tegan had no choice but to follow his flapping
  scarf and coat. This wasn't her idea of fun, playing some maniac game of
  tag, in and out of the low buildings. At least the Doctor seemed to have
  some sense of the geography of the place, avoiding the culs-de-sacs between
  the huts. Then they rounded a corner and ran straight into the workmen.
  There was a sudden tangle of limbs and a clatter of bicycles. Tegan managed
  to evade the grabbing hands, but with his great loose coat and his flying
  scarf the Doctor was an easier quarry. Looking behind her Tegan saw the
  security men closing in.
  Then came a brief flash of light and a short sizzling sound. The Doctor
  looked up from his struggle to see the Master had missed his aim at the
  workmen, but was still pointing the deadly weapon. With a howl of rage he
  shook off his assailants and dived for the Master, grabbing the device and
  hurling it across the asphalt path.
  'Sentimental fool,' hissed the Master, throwing him back against one of the
  huts. 'Thanks to you we're weaponless.' The Doctor hit the slatted walls
  with a thud that knocked the air from his lungs.
  If it hadn't been for the intervention of Adric and Nyssa at that moment he
  would certainly have been captured. At the approach of the workmen with
  their bicycles the two companions had shrunk back behind a water barrel
  outside one of the huts. Adric knew that the Watcher had brought them there
  to help the Doctor, but until the moment came he hadn't been sure exactly
  how.
  Unfortunately Tegan had a very similar idea. As the two security men came
  pounding up to the scene she rushed forward waving her arms and shouting at
  the top of her voice, 'You've got all this totally topsy-turvy. The
  Doctor's here to help, and if you stop him it could be the last thing
  you'll ever do.'
  At the same time Adric had moved out into the open. He hadn't intended to
  topple the water barrel on the way, but the result certainly heightened the
  atmosphere of total confusion that was suddenly unleashed on the Pharos
  Project.
  While Nyssa signalled to Tegan to stay quiet, Adric declared loudly: 'Nyssa
  and I have heard your message across the universe and have come to answer
  your call.'
  The Master tugged at the Doctor's coat. 'You and I have work to do,' he
  whispered. Though reluctant to leave his companions, the Doctor was bound
  to agree. He followed the Master discreetly out of sight, around the corner
  of the hut.
  'Message?' one of the security men was saying. 'What? Who are you people?'
  It was Nyssa's turn for theatricalities. 'We are the alien beings you
  seek.'
  'We are intelligences from deep space,' Adric chimed in.
  The chief security man gestured ineffectually for silence. 'Now just a
  minute . . . Please!'
  'Every word of this is true,' Tegan shouted, her outback Aussie voice
  easily the loudest present. 'Well, come on, you lot! Don't just stand
  about. Let's go and see someone in authority!'
  
  The Doctor found himself running towards the antenna on his own. At the
  absurd risk of being seen by the security men the Master had hung back,
  losing precious moments to scan the ground. He wasn't going to let the
  Doctor's delicate sensibilities deprive him of the companionship of his
  favourite weapon.
  Luckily for the Master, the two security men and the workmen were engrossed
  in their interrogation of Tegan, Adric and Nyssa. He scooped up the weapon
  and, with a sardonic glance in the direction of the antenna, where the
  Doctor could be seen beginning the long climb up the steel ladder, he
  doubled back towards the computer room.
  The technician was stirring. His first, and last, conscious awareness was
  of powerful arms grabbing his white coat and hauling him to his feet. He
  felt cold metal against the side of his head, and then there was a sizzle
  and a smell of ozone and the world exploded into a giant dome of light.
  The Master pocketed the cassette recorder. A moment later he and the plump
  fluted column had vanished from the computer room.
  From the door of the TARDIS the Watcher had seen the Master retracing his
  steps to the computer room, as he saw now the Doctor's perilous ascent of
  the Pharos antenna. These were the conditions of the moment he knew had to
  come. In his mind was a clock, its hands closing on the inevitable vertical
  of midnight.
  The higher the Doctor climbed the more the wind lashed at him, bellowing
  out his coat like some wild red sail. His hands ached on the cold metal
  rungs, and at one point he paused to fumble in his pockets for gloves. He
  took the opportunity to look down to the dizzyingly diminished enclosure,
  just in time to see the tiny figures of Adric, Nyssa and Tegan being
  marched into the building by the security guards.
  There were no gloves, and by the time he arrived at the parapet his
  knuckles were blue. He leant for a moment against the rail and took stock
  of the geography. The articulating structure he was standing on was
  designed to revolve about the base as the antenna tracked across the sky.
  The swaying metal walkway ahead formed a long thin bridge across to the
  bowl of the parabolic aerial. The cable strapped to the railing like the
  sinew of a giant arm lead back from the bowl to a large box-like
  construction near where the Doctor stood. He pushed open the door and
  looked inside. As he had deduced from the cable, it was the antenna control
  room. What he had not expected to find was the Master, calmly making
  connections to an electrical conduit in the wall.
  'I decided to use my TARDIS after all,' the Master said without
  interrupting his work.
  The Doctor noticed the ugly column in one corner of the room. He took out
  the light speed overdrive from his top pocket. 'You didn't miss this?'
  'I gave you that to demonstrate my trust, Doctor. But I do not take foolish
  risks. There is the real light speed overdrive.'
  The Master waved towards the work-bench, where a similar device glowed
  among the dials and switches. 'We have only to connect this feed from the
  computer room, and the job is done.' He handed the end of the jumper wire
  to the Doctor. 'As you devised the plan, I think the honour should be
  yours, Doctor.' And with that he strolled out onto the parapet.
  The Doctor ran his eye over the work-bench. The light speed overdrive was
  hooked into the oscilloscope that metered the radio frequency output to the
  antenna. It wasn't an ideal arrangement, but as a quick improvisation it
  was perfectly workable. Once again the Doctor had to admit admiration for
  the Master's ingenious practicality. With the sonic screwdriver in one hand
  
  and the jumper wire in the other he began to complete the task.
  Outside, the Master looked down over the rail to the enclosure far below,
  where with a flurry of activity the establishment was beginning its working
  day. His thin lips curled into a smile. 'Alien intelligences! I'll show
  them the quality of alien intelligence.'
  From his pocket he took the looted cassette recorder and, softly in order
  to avoid alerting the Doctor in the room behind him, began to speak into
  it.
  'Peoples of the universe. Please attend carefully. The message that follows
  is vital to the future of all of you . . . '
  With a sense of satisfaction the Doctor rapidly checked the connections he
  had made. The moment had come to throw the switch.
  A deep grinding sound shook the room as the whole steel structure began to
  move, rotating the basket-like bowl of the antenna to point at a pin-prick
  in the heavens he had plotted on the co-ordinator. He studied the small
  circular screen of the oscilloscope excitedly and reached out to make a
  minute adjustment to one of the dials. The cable was now feeding the
  analogue converter with a regular flow of digital input from the computer
  room, and as far as the Doctor could judge from the feedback patterns the
  transmission link was established. The data was reaching the CVE, and it
  was stabilising!
  He heard a chuckle behind him. 'So it works! Congratulations, Doctor. I
  always knew you would do it.'
  'You did most of this,' the Doctor conceded generously.
  'Oh no . . . I was little more than a humble assistant. I have learnt a
  great deal. And now it is time for you to go and explain the presence of
  your friends. There's quite a hubbub outside.'
  The Doctor got up from the work-bench. 'Quite right. We'd better leave this
  until the new equilibrium is established. A mistake now could destroy
  everything.'
  'I know that, Doctor. And it could happen so easily.'
  Something in that level, mocking voice made the Doctor hesitate at the
  door. 'What do you mean?'
  The cold dark eyes gazed back unblinkingly. 'The universe is hanging on a
  thread. A single inversion pulse down that cable and the CVE would close
  forever. Even a humble assistant could do it.' While he spoke the Master
  placed the cassette machine on the work-bench and bent the goose neck of
  the talk-back microphone down towards it. His finger prodded the play-back
  button.
  The Doctor listened in horror to the whisper that came thinly from the
  miniature loudspeaker. 'The message that follows is vital to the future of
  all of you . . . At the time of speaking the fate of the universe hangs in
  the balance, and the fulcrum of that balance is the Pharos Project on
  Earth. It is from there that I am speaking. The choice for you all is
  simple: a continued existence under my guidance, or total annihilation . .
  . '
  The Doctor had heard enough. 'Blackmail!' he exclaimed.
  'No, Doctor. I am simply reporting the state of affairs. I have the power
  now to save them or destroy them.'
  'You're utterly mad!' The Doctor made a move forward.
  But the Master already had the weapon levelled at the Doctor's head.
  'Please stay where you are. We cannot have the proceedings interrupted.'
  From his pocket he took the silver device the Doctor had seen him use to
  devastating effect on Logopolis and clipped it neatly on to the end of the
  light speed overdrive. 'Now the CVE is mine, Doctor.'
  The Doctor edged away, as if intimidated by the weapon. He had no illusions
  about its unpleasant consequences, but his main object was to get nearer
  the door. There was a good chance the CVE had stabilised by now, and it
  would only be under the Master's power as long as the link between it and
  the improvised apparatus held. The Doctor remembered the long cable that
  
  snaked between the control room and the parabolic aerial. Perhaps there was
  a way to stop this final catastrophe. The Doctor dived out through the
  door, slamming it behind him.
  The metal plates of the swaying walkway clattered under his feet. Dwarfed
  by the gigantic proportions of the great bowl, the Doctor raced across the
  tenuous bridge that hung in the air between the control room and the
  aerial. His eye scanned the handrail, tracing the path of the cable along
  its length. Somewhere there had to be a junction he could disconnect.
  Over the sound of the wind he heard the Master's voice behind him.
  'Don't make any plans, Doctor. Your future ends here.'
  The Doctor threw himself flat on the walkway as the beam struck sparks from
  the rail. Assuming a five-second recharge cycle for the weapon the Doctor
  scrambled to his feet again, ran on - and dived again. To his horror the
  shot did not come. The Master had outguessed him, and now he was a sitting
  target.
  The Doctor jerked his head round to look back, and was astonished to find
  the Master's face grinning at him from behind the glass of the control room
  window. Of course! With his target so close to the antenna the Master dared
  not risk firing a high-energy beam. A ricochet could disrupt transmission.
  But what was he up to now?
  The Doctor dismissed the question and, obeying the First Law of Crisis,
  concentrated on the cable. At the point where he now lay, it branched away
  from the railing and ran directly under the walkway. He put his head over
  the edge and saw the smooth line of the insulation interrupted by a bulky
  contusion. The connector he was looking for lay directly beneath him. So
  did a postage-stamp-sized stretch of asphalt car park. But he tried not to
  think of that as he climbed through the railing.
  At that instant he discovered what the Master was up to in the control
  room. The whole walkway began to tilt with alarming speed, pitching him
  forward into space. The Doctor grabbed for the only handhold he could see,
  the cable itself.
  It sagged under his weight, and then with a sickening snapping sound the
  ties on either side broke away from the struts, jerking him down until he
  hung fifteen feet below the girders. His hands gripped the bottom of the U
  formed by the cable, and he swung there with nothing beneath the soles of
  his shoes but thin air.
  The positive aspect of the situation was that he now had control over the
  connector. The negative side of life had also to be faced: if he were to
  separate the connector, as it flew apart there would be very little chance
  of holding on to both ends. And whichever end he chose would almost
  certainly not bear his weight.
  But the Master was poised to destroy the CVE. The cable powered a gigantic
  weapon that put the whole universe in the palm of his hand.
  The angry thought silenced all debate. Inching his fingers backwards and
  forwards the Doctor began to unscrew the casing.
  A picture floated into his mind of a distant, vaguely formed figure, folded
  back from the time that was to come by the turmoil of the present. Even as
  he methodically continued the rocking movement of his hands, screwing out
  the thread millimetre by millimetre, he had a sense of those eyes watching
  him: his own eyes from the future.
  Tegan, Nyssa and Adric were being marched out of the building towards the
  waiting van when one of the security guards shouted, 'Up there! Come on!'
  The exclamation triggered a sudden flurry of officialdom towards the base
  of the antenna, and the three companions found themselves abandoned by most
  of their interrogators.
  Adric cricked his neck upwards, and gasped to see the tiny figure swinging
  from the loop of cable below the walkway. The Doctor's plan must have gone
  hideously wrong. Officials were clambering up the ladder, and for a moment
  
  there seemed to be a chance they would reach him if he could hang on long
  enough.
  But as the helpless companions watched, the loop of cable sprayed out a
  cascade of sparks and came apart. For a fraction of a second the tiny
  figure swung on a single thread. And then it snapped.
  Adric, Nyssa and Tegan ran across the asphalt towards the hideously
  crumpled shape on the ground. It seemed impossible that he should still be
  alive. But they saw the contorted figure move, and a feebly lifted arm
  motioned them to stay back.
  Adric, who was closest, heard the familiar voice. 'This is the end . . .
  but the moment has been prepared for.'
  The Doctor struggled to lift his head, and reached out a hand towards the
  shadows behind him, as if he expected someone to be there. Adric blinked:
  there was someone there. A vague featureless figure stepped forward without
  a sound and took the Doctor's hand. It was as if the Watcher had been
  waiting there at the base of the antenna for the Doctor's fall.
  Tegan's voice was a hoarse whisper. 'What's happening to him?'
  The Doctor's arm contracted, drawing the Watcher towards him, closer and
  closer until the two shapes seemed to blend. The faces melted together and
  became formless.
  'He's changing . . . ' said Adric. 'The Doctor's regenerating.'
  Nyssa stared as the Doctor and the Watcher melted into a blur. 'So the
  Watcher was the Doctor all the time . . .!'
  The figure on the ground straightened its limbs and sat up slowly. A
  smoother, younger face was beaming somewhat vacuously up at them.
  'Well, that's the end of that,' said a voice they had not heard before.
  'But it's probably the beginning of something completely different.'
  
SOURCE: textdata/thevault/Vault2.0.-.Fiction-and-audiobooks/Books/Dr Who/041 - Doctor Who - Logopolis.pdf