Elspeth McGillicuddy is down from Scotland for a holiday and boards the 4:50 train from Paddington station to visit her friend, Miss Marple. During the journey, another train pulls alongside, and through the window Mrs McGillicuddy witnesses a tall, dark man strangling a blonde woman. She reports what she has seen, yet no one takes any notice. There is no report of any murder, no dead woman found on any train, and the police have no record of any...

Hercule Poirot becomes entangled in a nasty web of family secrets when he comes across a fresh murder at an English country manor.