Elspeth McGillicuddy is sweet, sensible, and generally not given to hallucinations. Until she boards the Paddington Station train for St. Mary Mead and becomes a witness to what appears to be a murder. But was she? She claims she saw a strange man strangling a woman in adjoining train – a crime no one else saw, no one else reported. Except her friend Miss Jane Marple. And the indomitable sleuth is returning to the scene of the crime to discover just exactly what Mrs. McGillicuddy saw.