When the Club Bermuda, a gambling club run by Marty Fain, is held up by petty gangster Johnny Warjak, Fain offers to reimburse his customers for their losses. Among the customers claiming losses is society woman Linda Vickers. Fain tells her privately that he knows the jewels she was wearing were paste, and when she insists that they were insured, he agrees to double her claim if she can prove it. Linda then accompanies Fain to her apartment, where she admits that she has no insurance policy. The two have a drink together and begin an affair. The next morning, Linda is wakened by homicide detective Lieutenant McReady, who informs her that Warjak was killed and that his murderer used her car to make his getaway. Although Linda realizes that Warjak must have been killed on Fain's orders, she provides an alibi for him and does not tell McReady that she left her car at the club. Later Linda and Fain take a drive in the country and talk about their pasts. Linda explains that her "memory" now earns her living. Fain then offers to pay her $18,000 for her "diamonds." When they return to town, they find Linda's brother "Doc," a recent medical school graduate, waiting for her. Doc disapproves of Linda's relationship with Fain, and the following night, at the Club Bermuda, Linda returns Fain's check and breaks off their relationship. The next evening, Doc returns to the club to apologize to singer Toni Peters for his drunken behavior the previous night. While he is there, Fain is at the apartment of gambler Nelson Clark, who owes him money. Clark pulls a gun on Fain, who kills him and then, wounded, manages to return to the club. Fain's men ask Doc to attend to him. Later, afraid that Doc will report the gunshot wound, as he is legally required to do, Fain's men follow him from the club and kill him. The police suspect Fain of killing Clark and Doc, but Toni, who has been beaten by Fain's men, refuses to testify that Doc was at the club on the night that Clark was murdered. McReady then asks Linda to help them put Fain in jail. She begs Fain to take her back, and when he is out of the room, steals his gun. After the police identify Fain's gun as the weapon that killed Clark, McReady asks Linda to help him trap Fain. Through a ruse, Linda lures Fain to Toni's apartment, where he admits that he killed Clark. The police secretly tape Fain's confession and arrest him. Later, McReady joins Linda as she walks away from her past.