The story follows two strangers a famous tennis star Guy Haines and a charming wealthy high-profile but psychopathic man Bruno Anthony who are fellow commuters on a train. Bruno suggests that because each of them has to "eliminate" someone, they should "exchange" murders, and that way neither will be caught. For Guy Haines, it's nothing more than the curiosity for the charming socialite and his murderous theory, but when the psychopath takes the first turn of the deal; he knows himself already framed for the bargain.