Adapted from Patricia Highsmith's novel, Strangers on a Train takes as its central proposition the meeting and ensuing guilty association of two complete strangers, Granger and Walker. Walker buttonholes Granger, a star tennis player anxious to remarry but with a clinging wife, and initiates a hypnotic discussion of exchange murders. Walker then does 'his' murder (the wife), and threatens to incriminate Granger if he doesn't fulfil his half of the 'bargain' (Walker's father). Significantly, Hitchcock didn't use much of Raymond Chandler's original script, because Chandler was too concerned with the characters' motivation. In place of that, Hitchcock erects a web of guilt around Granger, who 'agreed' to his wife's murder, a murder that suits him very well, and structures his film around a series of set pieces, ending with a paroxysm of violence on a circus carousel, when the circle Granger is trapped within is literally blown to pieces, leaving Walker dead beneath it and Granger a free man again.