The Agatha Christie Hour

While visiting Badgeworthy, the home of the Carslake family, Matthew Armitage experiences a strange and frightening vision in a mirror in his bedroom of a man with a scar strangling Sylvia Carslake. Time passes, the First World War takes place, and then finally Matthew marries Sylvia Carslake. However, suffering badly from shell-shock, he nearly destroys his own marriage through an Othello-like jealousy and possessiveness, which threatens to destroy both him and Sylvia, until one night Matthew's vision of the man with the scar comes back to haunt him.

Is it possible for the dead to come back and possess the living? And is it possible to strangle oneself because of it? The fourth man in the railway compartment seems to think so, with his strange story about the doomed little chanteuse Annette and the love/hate relationship that she shares with the backward Felicie Bault.