Late one night, real estate agent E. V. "Marsh" Marshall is meeting secretly with his married lover, Paulie Nevins, at a park when they overhear three men discuss robbing a nearby house of $350,000 worth of jewelry when its occupants go on vacation in a few days. When Marsh states that he wants to report the incident, Paulie points out that if they reveal they were together, her husband Ralph, Marsh's boss, will learn of their affair. Although Marsh wants Paulie to leave her husband and marry him, Paulie refuses, as she does not want to give up Ralph's wealth. When Paulie returns home, she finds the jealous Ralph waiting for her, and after she asks for a divorce, he viciously beats her. In the morning, Ralph attempts to apologize to Paulie, but she will not talk to him. Paulie then goes to Marsh's apartment, and he is horrified when he sees her wounds. Marsh immediately calls the office to confront Ralph, but Paulie whispers at him to make an excuse instead about his lateness. While they are whispering, however, Ralph is on the line and hears the bells on the distinctive bracelet that he gave to Paulie, and realizes that she is having an affair with Marsh. When Marsh arrives at the office, Ralph tells him that he is taking Paulie on a long vacation to revive their marriage, and that he wants Marsh to head the office while they are gone. Although he is uneasy, Marsh agrees, then staggers out, ignoring the congratulations of Ralph's secretary, Kathy Stevens. Several days pass as Paulie, watched intently by Ralph, is unable to sneak away to meet with Marsh. When Paulie does get away, she tells Marsh that she cannot face going on the trip with Ralph. Hoping to get enough money for them to run away together, Paulie tells Marsh that she wants him to hijack the thieves they overheard after they steal the jewelry. Shocked, Marsh tells her that they cannot start a new life together based on a "rotten foundation," and in reply, Paulie tells him about her impoverished childhood. Marsh remains intractable, and so Paulie leaves. The next morning, however, Marsh, unwilling to lose Paulie, calls to tell her that he will carry out her plan. Marsh goes to the site of the intended robbery, the lavish home of Dr. Sam Lynbury and his wife, and pretends to be interested in buying it for his firm. Although Mrs. Lynbury refuses to sell, she gives Marsh a tour of the home, thereby enabling him to locate the safe containing the jewelry. Paulie then orders Marsh to concoct an excuse to force Ralph to work late the following evening, while she provides an alibi for herself by going out to a nightclub with their friends, Phyllis and Tom Rycker. Ralph, suspecting that Paulie is lying, rents an inconspicuous car and, after pretending to go to work, follows her to the nightclub. At the club, Paulie tells Phyllis that she has to say goodbye to her lover before she and Ralph leave. Phyllis agrees to cover for her if Ralph calls, and Paulie then picks up Marsh. Ralph follows them to the driveway below the Lynbury home, and while Marsh is successfully stealing the jewelry from the thieves, Ralph confronts Paulie. When Ralph pulls a gun on Paulie, they struggle for the weapon, and Paulie fatally shoots Ralph. Because the thieves are shooting after Marsh as they chase him, Marsh assumes that one of their bullets killed Ralph. Marsh and Paulie escape, after which the robbers find Ralph's body as well as Paulie's bracelet, which had come off while she was struggling with her husband. Realizing that with Ralph dead, they must stay in town to avoid suspicion, Marsh instructs Paulie to return to the club and pretend to be surprised when the police inform her about Ralph. Upon investigating the crime scene, Inspector Paley, Lt. Jennings and Sgt. Allen are unaware of the actual robbery and are baffled by the mysterious murder. Several days pass as the police continue their investigation and Marsh begins running the office with Kathy's help. Paulie, upset that Marsh insists they cannot risk being seen together, grows jealous of Kathy and fears that she is the real reason he is keeping his distance. Meanwhile, Kathy, afraid that Marsh, with whom she is in love, will be implicated in Ralph's murder, does not reveal to the police that Ralph had recorded a message in which he detailed his plans to follow Paulie and Marsh the night of his death. As Paulie becomes more irrational, Marsh begins to wonder about her true character, especially after she reveals that she, rather than the burglars, killed Ralph. Soon after, the two thieves, who have learned that Paulie is the owner of the bracelet they found, are confronted and murdered by their boss, Dr. Lynbury, who planned the theft of the jewels. Lynbury then goes to see Paulie and reveals that he orchestrated the robbery because years earlier, he secretly sold off his wife jewels, replaced them with paste replicas and now wants to collect the insurance on them by having the phony gems stolen. Bemused that so much trouble has come from the robbery of worthless jewelry, Paulie gives Lynbury Marsh's address so that he can reclaim the items before his duplicity is uncovered. Meanwhile, the police question Kathy, whom they suspect of having had an affair with Ralph because of misleading information given to them by Paulie. Marsh is infuriated by Paulie's betrayal, and later, discovers that Kathy has been trying to protect him. Marsh confesses all to her, and the supportive Kathy urges him to turn over the jewelry to the police. When they attempt to collect the loot from Marsh's apartment, however, they are confronted by the gun-wielding Lynbury. The police, who have been following Marsh and Kathy, arrest Lynbury, then take Marsh to Paulie's house. There, Marsh castigates Paulie for implicating Kathy in Ralph's death and states that he no longer loves her. The police arrest Paulie, and as she changes into street clothes, she looks out her window to see Marsh being embraced by Kathy. Although Marsh tells Kathy that he is not worth her love, she asserts that it is her decision to make.