let swap murder your wife and my father seemingly innocent conversation between two stranger bruno anthony and guy haines when they meet over lunch on a train journey . guy and a solid and respectable tennis player and whose problem be that his wife and the flirtatious miriam and would not divorce him so he can marry senator daughter anne and laugh the whole conversation off a a joke . the following week he isn not laugh any more . in a scene of classic hitchcock suspense and bruno stalk miriam through a carnival and strangle her . a he do and her glass fall off and we see the murder eerily reflect twice through her lens . cold hearted and amoral bruno and his part of the deal complete and approach an appalled guy expecting and even pressure him into wouldoing his bit . matter be not help when anne precocious and outspoken young sister turn up suspect guy of miriam murder . so accused of a murder he do not commit and expect to commit another and what be guy go to do . the power of this film be in the presentation of human being a have a murderous side to their nature and this hitchcock do to perfection .