In the small town of Bridgeport, California, gas station owner Jeff Bailey is tracked down by Joe Stefanos, a former business associate, who tells him that his boss, Whit Sterling, wants to see him the next morning in nearby Lake Tahoe. After he reluctantly agrees to meet with Whit, Jeff reveals to his trusting girl friend, Ann Miller, his recent past: Three years earlier, while working as a private detective in New York, Jeff, whose real name is Markham, and his partner, Jack Fisher, are hired by gambler Whit to find Whit's girl friend, Kathie Moffat. According to Whit, Kathie shot him and then disappeared with $40,000 of his money. Assured by Whit that Kathie will not be harmed, Jeff locates her in Acapulco and immediately falls in love with her. Deducing Jeff's mission, Kathie insists that she did not steal Whit's money but was only trying to flee his romantic tyranny. Jeff and Kathie soon become lovers and are about to leave Acapulco together when Whit and Joe show up at Jeff's hotel. Jeff tells Whit that he was unable to find Kathie and offers to quit, but the suspicious gambler demands that he continue the search. That night, Jeff and Kathie board a north-bound steamship and begin a happy life together in San Francisco. Eventually, however, Fisher, who was to receive half of the $10,000 that Whit offered for Kathie's return, tracks the couple to a remote cabin and threatens Jeff. When the two detectives begin to fight, Kathie calmly shoots Fisher dead and leaves Jeff to bury him. The stunned and heartbroken Jeff then learns that Kathie had, in fact, stolen Whit's $40,000. After Jeff concludes his story, Ann pledges her love and promises to wait for him while he goes to Tahoe. At Whit's Tahoe vacation home, Jeff discovers that the double-crossing Kathie has returned to the gambler and has told him about their affair. Because of this, Jeff feels pressured to accept a job retrieving some tax documents that Whit claims are being used by Leonard Eels, a San Francisco lawyer, to blackmail him. As prearranged by Whit, Jeff accompanies Eels's secretary, Meta Carson, to Eels's apartment, where Meta is to steal the lawyer's briefcase and then pass the damning tax papers on to Jeff. After talking with the soft-spoken Eels, however, Jeff suspects that the revenge-hungry Whit is about to murder the lawyer and frame him for the crime. Although he is unable to prevent Eels's murder, Jeff does trick Kathie into revealing that she, Meta and Joe were involved in his demise. When confronted by Jeff, Kathie confesses that she told Whit that he, Jeff, killed Fisher and she was forced to sign an affidavit attesting to such. Kathie also reveals that, while Meta was stealing Eels's briefcase, she put the affidavit in his apartment safe. Thus implicated in two murders, Jeff pretends he is still in love with Kathie and learns from her the whereabouts of Eels's briefcase. After Jeff, who is now the target of a police manhunt, retrieves the papers, he informs Kathie that he will mail them to the Internal Revenue Service unless Whit gives him the affidavit. Instead of relaying Jeff's demands to Whit, Kathie orders Joe to follow The Kid, a young deaf-mute who works at Jeff's gas station, to Jeff's mountain hideout. As Joe is about to shoot Jeff from a cliff, however, The Kid ensares him in his fishing line and causes him to fall to his death. Jeff then sneaks into Whit's Tahoe home and reveals Kathie's subterfuge to him. After Whit agrees to Jeff's demands for $50,000, plus Kathie's admission of guilt in Fisher's murder and the implication of Joe in Eels's death, Jeff makes plans to leave with the still loyal Ann. When Jeff, who is being hunted by Jim, Ann's devoted childhood sweetheart, returns to Whit's to collect his money, however, he discovers that Kathie has killed the gambler. Knowing that the authorities are following The Kid south, Jeff agrees to flee to Mexico with Kathie, and deliberately drives into a police stake-out. As the police descend upon their car, Kathie angrily shoots and kills Jeff, then is killed by the police. Later, after The Kid tells her that Jeff had gone back to Kathie, Ann leaves Bridgeport with Jim.