Steve Clark arrives by bus in a suburb of Los Angeles, goes immediately to a bank and places several bundles of bank notes in a safety deposit box, then takes a job as a taxi driver. One night, at a restaurant, Steve picks up Julie Saunders and her drunken escort, Harry. Julie wants to go home but Harry is trying to lure her to his place. Steve pulls over, ejects Harry, takes Julie for a cup of coffee then drives her to her house, where she lives with her aunt Cora, a bitter, ever-complaining old woman. Before they part, Steve and Julie kiss. The next day, Steve spots Julie reporting for work as a waitress at a malt shop and arranges a date with her for that evening. Aunt Cora complains to Julie, her only relative, that she is leaving her alone again and, when Steve calls for Julie, feigns a fainting spell. A storm then knocks the power off, and Julie asks Steve to go upstairs to the attic to fix the fuse. Julie and Cora have a vicious argument and Cora tells her to leave. Although Julie stands to inherit the house, which she hates, she leaves, and she and Steve are married by a justice of the peace. Steve then tells Julie that he was married before but has been divorced for a year. Out of earshot of Julie, Steve leaves a phony message for himself at his apartment building, and, when they arrive there, he pretends to phone his lawyer. Afterward, he tells Julie he has learned that his divorce is not final and until things can be straightened out, Julie should stay with her aunt. Steve visits Julie there and begins to poison Cora. When Julie suggests calling a doctor to examine her aunt, Steve tells her that he has "fixed" Cora's tea and juice. He reveals that he has $200,000 in the bank but cannot touch it as the police might start asking questions, as might a man called Rogers. When Cora dies, Steve intends to plant the money in a trunk he saw in the attic and make it appear that Julie's eccentric aunt hoarded it. Julie tries to phone the police, but Steve reminds her that she served the poisoned drinks and that they cannot testify against each other as they are really married. After Steve leaves for work, Mrs. Ferguson, a neighbor, pays a call and, after seeing Cora in bed, summons her own doctor, who gives Julie a prescription to fill. As Julie leaves the pharmacy, Steve is waiting in his taxi and throws the medicine away. Cora dies and Steve and Julie work the "money-in-the-trunk" routine, with Julie "inheriting" all of it. However, Julie's lawyer, Donald Harper, who does not know that she is married, advises her that it will take several months to probate the will. Later, in a cocktail lounge, Steve runs into an acquaintance named Charlie, who addresses him as Freddie Howard and tells him Rogers is looking all over the East for him. Later, Steve becomes jealous when Julie receives flowers and a dinner invitation from Donald and slaps her. To make up, Steve invites her to meet him at a restaurant for dinner, but while Julie is waiting, she is spotted by Donald, who asks her to join him. While at Donald's table, Julie receives a phone call from Steve, who is in a booth across the restaurant and orders her to get rid of Donald. Julie inadvertently fails to hang up the phone properly, and Steve hears her tell Donald that she cannot tell him then what is troubling her, but will come to his office the first chance she gets. When Julie and Steve leave in Steve's cab, Donald jumps in and questions Julie about what she is afraid to tell him, but she denies saying anything. Later, at home, Julie convinces Steve that she is on the level with him, but he soon discovers that she is planning to leave him. When Rogers, tipped off by Charlie, comes to the house looking for his share of the $200,000, the haul from a Denver bank holdup in which they were both involved, Steve draws a gun and kills him. After Steve and Julie dispose of the body, Julie tells Steve that she cannot continue and that she is in love with Donald. Steve, however, insists that he is in love with her and will do anything to keep her. Later, a Mr. Haynes makes a claim for $100 against Cora's estate, saying that four years earlier, he had lent that sum to Cora's husband and has an I.O.U. from him. Haynes arouses Donald's suspicions and he discovers that Steve was involved in the Denver robbery and is no longer working for the cab company. While investigating Steve's rooming house, Donald finds Steve and Julie's certificate of marriage. The manager discovers Donald and calls Steve at Julie's, and Steve recognizes the description as matching Donald's. When Donald arrives at the house, Steve draws a gun on him. Steve admits to Donald that he is a bank robber, but states that Julie is an innocent victim of his schemes. Steve then turns up the volume on a radio to mask the sound of his shooting Donald, but the noise attracts a passing patrol car and the officers investigate, arriving in time to shoot Steve before he shoots Julie so that they can be together always. Arrested as Steve's accomplice and sentenced to ten years in prison, Julie is left to wonder whether Donald will be there when she gets out.