Duke and Jeanie Benson, a notorious outlaw couple, are hiding under false identities in a quiet suburban town. Their lives take a turn when Duke reads a newspaper story about a sweepstakes winner who has yet to claim his prize, revealing that Duke himself holds the winning ticket worth $150,000. Realizing his potential to escape his life of crime, Duke becomes determined to claim the jackpot, but he must do so without getting caught by the authorities. Eager for a change, Duke decides to hop on a train heading towards Kansas City, the city where he originally purchased the ticket, while Jeanie plans to fly there with a third person who will claim the winnings on their behalf.
At the train station, Frank Evers, a reporter played by Brian Donlevy, boards the train and immediately crosses paths with Duke, sensing an opportunity for a story. Later, in San Bernardino, another passenger, Anne Marvis, portrayed by Gloria Stuart, boards the train. When she notices the door to Duke’s private car left open, she discreetly hides in his bed, setting the stage for potential complications. Both Duke and Frank find themselves attracted to Anne, creating a complex web of relationships on the journey.
Jeanie, suspecting that Duke's intentions might be more than innocent, boards the train after her plane is grounded, and she quickly becomes suspicious of the growing closeness between Duke and Anne. She pulls a gun, fearing an affair, but Duke eases her worries by claiming that Frank is Anne’s husband, a lie they all participate in to keep the peace. From that point, Frank and Duke, who is actually a G-man, listen through a hidden device to the train conductor's room, gathering intelligence on the couple’s plans. They learn that Jeanie plans to leave Albuquerque by plane and head to Kansas City, where all their plans are set in motion.
Throughout the journey, Duke attempts to flirt with Anne, but she rebuffs him, revealing herself to be more than just a fellow traveler—she's a Los Angeles-based newspaper reporter subpoenaed to testify before a grand jury about a political scandal she uncovered. Her revelation surprises Duke, who is trying to navigate his criminal plans. Frank, still undercover, confronts Anne about her true role, only for her to assert her identity and her commitment to the truth.
As the train continues westward, complications intensify. In Topeka, a porter inadvertently finds the listening device planted in Duke’s room, leading to a scuffle where Duke hits the conductor. Meanwhile, Anne receives a message indicating it’s safe for her to return to Los Angeles and disembarks from the train. Duke, spotting Frank in pursuit, quickly enters a taxi with Anne to hide from the authorities, heading to a sanitarium where Duke’s wife Jeanie is waiting.
At the sanitarium, Jeanie is upset to see Duke with Anne, but their tense reunion is interrupted when they learn that the true lottery winner has already claimed the prize. Duke, desperate to claim his share, sends his lawyer Rickert to challenge the official claim. While Rickert is away, Duke attempts to convince Anne to leave with him after he secures the winnings. She initially agrees, but Duke secretly locks her in her room, planning to escape alone. Jeanie, showing her loyalty, helps Anne by opening her room's shutters, allowing her to escape. Anne manages to hitch a ride on a truck, only to discover that the driver is part of Duke’s gang who returns her to the sanitarium.
The situation escalates when Duke, realizing Jeanie’s involvement, physically assaults her. Frank, disguised as an insurance agent, arrives to support Rickert but arrests the gang as violence erupts. In a final confrontation, Duke pulls out a gun, shoots Frank as police arrive, and tries to take Anne with him. However, Jeanie, in a moment of heroism, shoots Duke, ending his reign of crime. She then breaks down crying over his body, thankful that Anne and the others are safe. The police capture the gang, and Anne, relieved, finds herself free alongside Frank, with the two of them riding the train once more—this time as a married couple, ready to face whatever comes next.
> "You can't run away from your past, but you can make choices about your future."
