Based on The Wheel Spins by Ethel Lina White, this Hitchcock thriller is about Iris Henderson (Margaret Lockwood), who is traveling through Europe by train and soon learns that her fellow passenger, Miss Froy (May Whitty), has disappeared, and no one remembers her. Is Iris just seeing things? Has a hit on her head ruined her hold on reality? Will she fall in love with clarinet player Gilbert (Michael Redgrave) and leave her fiancé?

Originally called The Lost Lady, this was to be directed by Roy William Neill. A crew went to Yugoslavia to shoot some background shots, but when the police accidentally learned that the country wasn’t treated well in the story, they kicked the crew out. A year later, as Hitchcock was trying to fulfill his contract, he took on this story.

The characters of Charters and Caldicott, played by Basil Radford and Naunton Wayne, were so popular that they would appear in three more movies: Night Train to Munich, Crook’s Tour and Millions Like Us. While not called by name, they also played versions of the characters in The Next of Kin, Dead of Night, A Girl In a Million, Quartet, It’s Not Cricket, Passport to Pimlico and Stop Press Girl as well as radio appearances. The 1979 Hammer remake featured Arthur Lowe as Charters and Ian Carmichael as Caldicott, while a modern-day TV series from 1985 starred Robin Bailey as Charters and Michael Aldridge as Caldicott.

You can watch this on YouTube.