One, Two, Buckle My Shoe

Poirot goes to the dentist, which is a routine errand, and shortly after he leaves the surgery the dentist is found shot dead. The death looks like suicide, and the police would be glad to let it be one. But Japp calls in the man who was, inconveniently for everyone, the last respectable witness to see the dentist alive.

The more Poirot looks at the tidy version of events, the less it holds together. The dead man's household is full of people with reasons to prefer a quick explanation, and a few of them are hiding things that have nothing to do with the shooting, which is usually where the truth lives. Joanna Phillips-Lane plays two women in the same house, and a young man called Frank Carter is played by Christopher Eccleston, still more than a decade away from the TARDIS. A dental practice is an odd place for a murder, which may be why the trick nearly worked.

Clive Exton and Agatha Christie wrote it, Ross Devenish directed. Philip Jackson's Japp does the official worrying. Joanna Phillips-Lane takes the twin roles of Gerda and Helen, with Peter Blythe as Blunt, Carolyn Colquhoun as Mabelle, Karen Gledhill as Gladys Neville, Laurence Harrington as Henry Morley, Rosalind Knight as Georgina Morley and Sara Stewart as Jane Olivera.

It is a neat, quiet episode in which the smallest details do the heavy lifting. Nobody notices small things like Poirot does, and the nursery rhyme of the title turns out to be fair warning: this is a story that counts on details, and the details are where the solution has been sitting all along. It is the kind of episode that rewards a second viewing, because the first one hides everything in plain sight. The surgery and the house give the case plenty of rooms to hide in.