text: <br /><br />"Lets swap Murders- your wife, my father"- seemingly innocent conversation between two strangers - Bruno Anthony and Guy Haines when they meet over lunch on a train journey. Guy, a solid, respectable tennis player, whose problem is that his wife, the flirtatious Miriam, won't divorce him so he can marry senators daughter Anne, laughs the whole conversation off as a joke. The following week he isn't laughing any more. In a scene of classic Hitchcock suspense, Bruno stalks Miriam through a carnival and strangles her. As he does, her glasses fall off and we see the murder eerily reflected twice through her lenses. Cold hearted and amoral Bruno, his part of the deal completed, approaches an appalled Guy expecting, even pressuring him into 'doing his bit.' Matters are not helped when Anne's precocious and outspoken younger sister turns up suspecting Guy of Miriam's murder. So accused of a murder he didn't commit and expected to commit another, what is Guy going to do? The power of this film is in the presentation of human beings as having a murderous side to their nature - and this Hitchcock does to perfection.