In London, Canadian war veteran Bill Saunders, whose two years in a German labor camp have left him prone to explosive fits of violence, accidentally kills a man in a pub. The crime is witnessed by black markeeter Harry Carter. Fleeing the police, Bill climbs through the open window of the apartment of medical assistant Jane Wharton. Jane promises not to report Bill's break-in if he allows her to go to work and leaves her apartment. Bill agrees and later in the street robs a man's wallet and buys new clothes, then waits for Jane outside the clinic. He follows her to a zoo and she grudgingly befriends him, agreeing to spend the afternoon with him at the racetrack. While betting on the races, Bill runs into Harry, who threatens blackmail. On the train returning to the city, Bill gets involved with a cardsharp and beats him up when the man refuses to continue playing. Bill and Jane jump the train and Jane is outraged at his violent behavior and leaves him. When a policeman questions him, Bill strikes him and is promptly arrested and sentenced to six months imprisonment and eighteen lashes for brutality. Upon his release, Bill runs into Harry, who suggests they become partners for a major heist, but Bill is evasive. Instead, he visits Jane, who had tried unsuccessfully to visit him in prison. She offers to get him a job as a supplies driver for the clinic and he gratefully accepts. Bill settles contentedly into his job, but Harry tracks him down and demands that he help him steal the clinic's penicillin to sell on the black market. Bill agrees on the condition that this is the only illegal job in which he will participate. On the night of the planned theft, Jane unexpectedly asks to ride along with Bill. When Bill tries to call off the heist, Harry refuses and Bill beats him up. He continues the normal delivery with Jane, taking the drugs to the homes of several sick children. The next night Bill searches for Harry, who goes to Jane's apartment to expose Bill. When Harry attempts to assault Jane, she stabs him with a pair of scissors, then flees to Bill's room. He returns to her apartment and discovers Harry still alive and takes him back to his own flat, where Harry dies. Panicked, Bill tries to arrange passage on the ship making the black market run, but the captain refuses to carry them unless Bill brings the penicillin. Bill returns to Jane and tells her Harry was not in her apartment and so must be alive, and convinces her to come away with him to America. She discovers the bloody scissors in his pocket, however, and determines to give herself up to the police. Bill tries to dissuade her, but eventually agrees their only chance at happiness is to face up to their actions.