The Devil's Foot

Holmes, reluctantly, is on holiday. An illness has put him in Cornwall with Watson for company, and he is bored, which for Holmes is a dangerous state. The locals are about to provide the cure. After a quiet evening at home playing cards, three people from the same house are found in a terrible state the next morning: the two Tregennis brothers are babbling and lost to sudden mental illness, and their sister Brenda is dead, her face twisted into a look of terror. The local doctor talks of apoplexy and sudden madness. Holmes calls it an interesting morning.

The case is a strange one even for him. Dr Leon Sterndale, the explorer, hovers over the investigation with the air of a man who knows more than he says, and the Tregennis family, it turns out, has its secrets. Holmes, delighted to have something to think about, works the puzzle with a relish that borders on indecent, and at one point experiments with the poison himself, nearly paying for the curiosity with his wits. Watson, as ever, is the one who has to pull him back from the edge, and the script makes that a physical effort rather than a word of advice.

Ken Hannam directed, from Gary Hopkins, John Hawkesworth and Conan Doyle. Denis Quilley gives Sterndale real presence, Damien Thomas makes Mortimer Tregennis genuinely unpleasant, and Norman Bowler, Peter Shaw and Christine Collins are the family undone. Michael Aitkens, Freda Dowie and John Saunders keep the village in frame.

The answer lies in a poison brewed from the devil's foot root. And before Holmes can move, the score is settled in his place. It is a nasty little story, one of the darker ones, and the episode has the sense to play it straight. Cornwall has rarely looked more beautiful or less safe. It is also a rare outing for a holiday Holmes, and the gap between the scenery and the case is the whole joke.