After twenty-five-year-old Steve Nordstrom is released on probation after serving a brief sentence in the Los Angeles County Honor Rancho for assaulting a man who insulted his girl friend, he visits police lieutenant Andy Doyle to thank him for arranging for Steve to serve his time at the Rancho instead of in jail. Later, Harriett Owens, Steve's girl friend, arranges an interview for him with her boss at a trucking company and Steve is hired to do a trial run. That night, on his way home from Harriett's apartment, Steve is attacked by Carl Fowler, the man he assaulted, who is seeking revenge for a scar Steve inflicted on him. Mindful of the terms of his probation, Steve offers little resistance and is badly beaten. When he recovers consciousness, Steve has amnesia and finds himself in a strange town, where Polly Gunther, a truck stop café owner, tries to help him and names him Eddie Thornton. Meanwhile, Harriett and Andy try to find out what has happened to Steve and suspect that Fowler may be behind Steve's disappearance, but Fowler has established an alibi for the time of the attack. After a few days working as an auto mechanic, Steve is hired by a prosperous businessman, Morton Ramsey, as a handyman and gardener at Ramsey's luxurious home. Unknown to Morton, his wife Claire is having an affair with his friend, Bob Bradfield. When Claire discovers that Steve becomes very angry when it is suggested that he seek psychiatric treatment for his condition, she devises a scheme to frame him for the murder of her husband, thereby making her a rich widow. After Claire insists that Morton talk to Steve about seeing a doctor, Morton meets with him in the garage. Steve refuses to consider the matter, knocks Morton down and runs off, whereupon Bradfield enters the garage and kills Morton with a hammer that Steve was using. Later, Steve is arrested for Morton's murder and the news reaches Andy and his sergeant, Mike Duncan. After Steve is hospitalized for his condition, Andy takes Harriett to see him, but he does not recognize her and rejects all offers of help. Although Andy and Mike follow several leads, they cannot prove that Steve has been framed for Morton's murder. Dr. Ainsley, in charge of Steve's treatment, injects him with a drug that restores some of his memory, but he is unable to recall the first incident with Fowler or anything thereafter. Andy decides to try a treatment of his own and returns to the hospital with Fowler in custody. Steve recognizes Fowler immediately and tries to attack him. With his memory now fully restored, Steve remembers seeing Bradfield at the Ramsey home. Andy discovers the affair and interrogates Bradfield, who weakens, admits to killing Morton and implicates Claire. Later, a fully recovered Steve and Harriett prepare a meal for Andy and invite him to their upcoming wedding.
