The Crooked Man

Colonel Barclay is found dead beside his unconscious wife in a room locked from the inside, with no key anywhere, and the obvious answer is that Nancy Barclay killed him. She is arrested and cannot defend herself, because she is lying in a coma. Holmes takes one look at the setup and decides the obvious answer is wrong. He wants to know about the missing key.

The truth goes back further than the marriage. Years before, in India, Barclay cheated Nancy's first fiancé, a man who was left disabled and in exile because of it. That old wound explains the argument that ended in the Colonel's death, and it explains the curious animal tracks outside the window better than any burglar could. The episode dips into flashbacks for the colonial past, and the pieces of a betrayal that began in India click together. Nancy's coma means the story has to be reconstructed from everyone else, which gives the flashbacks their weight.

Denys Hawthorne plays Barclay as a man carrying guilt he never admitted, and Lisa Daniely's Nancy is tragic without being sentimental. Norman Jones and Michael Lumsden share the part of Henry Wood, the wronged man, and a very young Fiona Shaw turns up as Miss Morrison, an early credit for a career worth watching. Paul Chapman, Shelagh Stephenson and Catherine Rabett round out the household. Alan Grint directs, with the script by Arthur Conan Doyle, John Hawkesworth and Alfred Shaughnessy. Michael Cox produced, with music by Patrick Gowers and cinematography by Ray Goode.

The locked-room setup is a genuine puzzle, and the solution is a real surprise. The animal tracks are the sort of detail a lesser detective would file under the impossible. Holmes files them under interesting. But the deeper subject is the damage one betrayal does, spread over years and a continent. That gives the episode a weight most of the series's puzzles never reach.