Jeff Bailey, portrayed by Robert Mitchum, lives an unassuming life as a gas station owner in Bridgeport, California. He is in a relationship with local girl Ann Miller, played by Virginia Huston, and seems content with his quiet existence. However, his past is shrouded in mystery, a fact that soon begins to unravel when a stranger recognizes him and mentions that Whit Sterling, a notorious gambler played by Kirk Douglas, has been searching for him.
Before heading off to meet Whit, Jeff attempts to confide in Ann about his enigmatic history. His actual name is Jeff Markham, and he was once a private investigator in New York along with his partner Jack Fisher, portrayed by Steve Brodie. Their lives took a dangerous turn when they were hired by Whit to locate his girlfriend, Kathie Moffat, played by Jane Greer. Kathie had vanished after shooting Whit and making off with $40,000, and now Whit demands that Jeff finds both her and the stolen money.
Flashing back to those tense days, Jeff begins his investigation by speaking with Kathie's former maid, Eunice. He gathers evidence suggesting that Kathie packed for a warm climate and had been vaccinated, hinting at her possible escape to Mexico instead of Florida. Following the trail leads him to Mexico City and ultimately to Acapulco, where Jeff spots Kathie and they quickly become romantically entangled. He keeps his true motives hidden initially but eventually admits that Whit is searching for her. As their bond deepens, they plot to elude their dangerous past together.
However, their plans are thwarted when Whit and his henchman, Joe Stephanos, portrayed by Paul Valentine, arrive unannounced. Jeff lies to Whit about Kathie's whereabouts, claiming she has fled on a boat south, before he and Kathie attempt to escape north. They try to live low-key in San Francisco, confident that they won't be recognized, yet that naïveté proves fatal when Fisher spots them and blackmails Jeff for the stolen money. A violent altercation ensues, resulting in Kathie fatally shooting Fisher, before she abandons Jeff in the chaos, leaving him with a bank book depicting their criminal haul of $40,000.
Shifting back to the present, Jeff tells Ann that he has not seen Kathie since that fateful day, but he reluctantly heads to meet Whit to come clean about the encounter. Upon his arrival, he discovers that Kathie has resumed her relationship with Whit. The dialogue shifts when Whit hires Jeff to recover certain tax records that a lawyer, played by Ken Niles, is using to blackmail him. During a complicated series of events in San Francisco, Jeff meets the secretary Meta Carson, played by Rhonda Fleming, who informs him about the intricate scheme between Whit and Eels.
Before Jeff can set things right, disaster strikes as he finds Eels dead, leading him to uncover Whit's plan to frame him for the murder. When Jeff confronts him, the consequences escalate. Following a fresh trail of deception, he discovers that Kathie orchestrated a deadly scheme involving Whit, Eels, and even Fisher.
As the suspense builds, calamity strikes and she urges Jeff to escape with her, but in a moment of betrayal, Jeff contacts the authorities, leading to a tragic misunderstanding. A police roadblock awaits them, and in a moment of desperation, Kathie turns on Jeff, shooting him before both are gunned down by the police.
In the aftermath of these horrifying events, Ann questions whether Jeff truly intended to leave with Kathie, only to be misled by The Kid, Jeff's assistant. The Kid’s lie preserves Jeff's memory, allowing Ann to move forward with her life, knowing that Jeff's love, albeit complicated, was genuine. The final poignant scene leaves viewers reflecting on love, betrayal, and the looming shadow of past decisions.
