The adventures of Agatha Christie's famous Belgian detective, Hercule Poirot, adapted for television over more than twenty years and covering every Poirot book and short story ever written. This enormous lifelong project starring David Suchet takes the eponymous detective from England to Egypt, from country estate to weekend lodge, from dinner party to train ride, with his good friend Captain Hastings at his side, solving some of the most celebrated murder mysteries ever conceived.
Poirot's Christmas is interrupted by Simeon Lee, who believes his life is threatened. Simeon is soon killed and his diamonds stolen, and there is no shortage of down-trodden Lees on hand who might have done the deed.
A string of thefts at a student hostel run by Miss Lemon's sister ends in death, and Poirot has a number of plots and sub-plots to untangle, including smuggling and political manipulations. A certain mouse is the only witness to a string of murders and it also features at the climax.
Meanwhile, Poirot invites Japp to stay with him while Mrs Japp is away. Hastings is also off on his travels, and the dim police inspector vies with Poirot over the cooking.
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 killer 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 killing 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 is killed by poisoning with phosphorus. The "dumb witness" Poirot must fathom to solve the mystery is a dog.