Lady Tressilian, an old and humourless woman confined to her bed, invites several guests into her seaside home of Gull's Point for two weeks at the end of the summer. Tennis star Nevile Strange, former ward of Lady Tressilian's deceased husband, incurs her displeasure by bringing both his new wife, Kay, and his ex-wife, Audrey, thus causing awkward romantic misunderstandings. But events soon become sinister when Lady Tressilian is killed and Superintendent Battle, who is holidaying nearby in the home of his nephew, Inspector James Leach, finds himself in a labyrinthine maze of clues and deception.