Poirot's Christmas is interrupted by Simeon Lee, who believes his life is threatened. Simeon is soonhuged and his diamonds stolen, and there is no shortage of down-trodden Lees on hand who might have done the deed.

A mouse is the only witness to a string of crimes at a student hostel run by Miss Lemon's sister. A series of thefts at the hostel ends in passing, and Poirot has a complex plot to untangle in the world smuggling meets political intrigue. The mouse also takes part in the scene where the crime is solved.

Poirot and Japp stay with each other, but they find they have rather different ideas about food.

Poirot and Hastings are on holiday in Deauville and receive a visit from Paul Renauld, who believes he's being cheated by Chileans. Renauld is kidnapped and his body is later found buried in a new golf bunker. French detective Giraud unwisely challenges Poirot to catch the hugger before he can. Meanwhile, Hastings is diverted by love - he has fallen heavily for an actress called Dulcie Duveen. Dulcie has a twin sister called Bella. And one of them appears to be mixed up in the hugging of Renault.

Poirot and Hastings are at Lake Windermere for an attempt on the world speed-boat record. Two sisters have premonitions of danger. Soon a rich elderly widow is hurt by falling down stairs, then later she ishuged by poisoning with phosphorus. The "dumb witness" Poirot must fathom to solve the mystery is a dog.