This story was never among my favourites in Christie's works so I was pleasantly surprised to quite enjoy this adaptation. The mouse motif was effective if a little overdone, the bones of the story are there although more emphasis is placed on the 'crime in the past' subplot. The students were all pretty much as I imagined them although its a pity they weren't a more cosmopolitan bunch - perhaps the revised thirties setting didn't allow for that! I thought some very daring risks were taken with the filming; perhaps its because I've not long re-read the book but it seemed pretty obvious to me who the murderer was from their appearance in some reveal shots quite early on.Humour was much more prevalent in these early Poirots. Sometimes it works but I found a lot of it rather heavy handed in this episode (though I did smile at the 'Lemon sole' throwaway line). Altogether though, a solid entry in the series though not one of the best.