The Deadly Assassin
In the serial , the renegade alien Time Lord the Master ( Peter Pratt ) seeks to restore his life force by disrupting a power source that would destroy the planet Gallifrey along with his archenemy the Fourth Doctor ( Tom Baker ) . 
<triplet> Time Lord <subj> the Master <obj> has part <triplet> the Master <subj> Time Lord <obj> instance of <subj> Peter Pratt <obj> performer <triplet> Fourth Doctor <subj> Tom Baker <obj> performer