Directed by Alfred Hitchcock, Tennis pro Guy chances to meet wealthy wastrel Bruno on a train. Having read all about Guy, Bruno is aware that the tennis player is trapped in an unhappy marriage to to wife Miriam and has been seen in the company of senator’s daughter Ann. Baiting Guy, Bruno reveals that he feels trapped by his hated father. As Guy listens with detached amusement, Bruno discusses the theory of “exchange murders.” Suppose that Bruno were to murder Guy’s wife, and Guy in exchange were to kill Bruno’s father? With no known link between the two men, the police would be none the wiser, would they? When he reaches his destination, Guy bids goodbye to Bruno, thinking nothing more of the affable but rather curious young man’s homicidal theories. And then, Guy’s wife turns up strangled to death.
