Old wounds are reopened for the Argyle family when a man suddenly turns up after being abroad and claims that the black sheep of the family could not have murdered its tyrannical matriarch.

A wealthy woman holds a party at her Devon estate for family and friends, including old schoolmate Miss Marple. When a solicitor and the hostess herself are both murdered, Miss Marple tries to find a clever killer with a devious plan.

Miss Marple and her nephew, novelist Raymond West, embark on a coach tour of historic English houses with an eclectic group of characters at the behest of a late friend who had knowledge of an unsolved murder.