When Tommy and Tuppence visit an elderly aunt in her nursing home, Tuppence is concerned by the odd behavior of some staff and residents. So when Tuppence hears about Aunt Ada's sudden death and the disappearance of her friend Mrs Lancaster, she realizes her concerns were right.
Tuppence meets Miss Marple and together they follow a path of clues that lead them to the Norfolk village of Farrell St Edmund, where they find a community guarding an array of secrets. Only by getting to the bottom of these secrets do they begin to unravel the truth about the mystery of Aunt Ada's death and Mrs Lancaster's disappearance.