Inspector Slack has converted the parish hall into a police operations centre. During the Sunday sermon, the minister pleads for the murderer to confess. Later, Assistant Vicar Hawes calls the minister to tell him he wants to "confess," but he collapses before he can say more. Miss Marple suggests to Slack that it's time to set a trap for the murderer with the help of Hawes's landlady, Mrs. Salisbury.
After Miss Marple's friend witnesses a murder in a railway carriage running parallel to her own, Miss Marple engages a resourceful young woman to investigate. The search leads to a decrepit estate, where they suspect the body was dumped. But the seemingly innocent family who lives there have secrets of their own.