A tennis player named “Haines” (Farley Granger) is riding in a train car when "Bruno" (Robert Walker) starts talking to him. At first, everything seems normal; Haines assumes this man is simply someone who wants some company while enjoying a drink. It doesn’t take long for it to become apparent that both men are unhappy with their current circumstances. “Haines” is married to “Miriam” (Kasey Rogers), but he longs to …

Two men, Guy, an athlete with marital problems, and Bruno, someone lacking morals, meet and become "strangers on a train." Bruno proposes a scheme where Guy could eliminate his wife without raising suspicion, and Bruno seems to believe that Guy has given his consent. Bruno’s wickedness is clear, but the question remains about Guy. Is he as decent as he portrays himself? Perhaps his wife isn't so terrible, or maybe…