U.S. Army lieutenant Duke Halliday, Robert Mitchum, is robbed of a $300,000 payroll by Jim Fiske, Patric Knowles. When Halliday's superior, Captain Vincent Blake, William Bendix, suspects him of involvement, Halliday pursues Fiske into Mexico. Along the way, he encounters Joan Graham, Jane Greer, who is after Fiske herself, trying to recover the $2,000 she lent to her ex-boyfriend. The two team up, tentative at first, unsure if they can trust one another.
When Halliday is knocked down while stopping Fiske from slipping away, he draws the attention of Inspector General Ortega, Ramon Novarro. Halliday claims to be Blake, using the identification he grabbed from Blake after a brawl; Ortega lets him pursue Fiske but keeps a wary eye on his every move. The real Blake appears at Ortega’s office, confirming the suspicions and intensifying the pursuit.
Fiske stays one step ahead as the chase winds from Veracruz into Tehuacán and deeper into Puebla, with Halliday pressed from one side by Blake’s relentless pursuit. The two fugitives, Halliday and Graham, grow closer even as they weigh who they can trust in this razor-edged cat-and-mouse game.
Halliday and Graham eventually trace Fiske to a desert safehouse where Julius Seton, John Qualen, lords over a grim deal: $150,000 in untraceable bills in exchange for the payroll. After a brutal shootout, the couple is captured by Seton’s henchmen. Blake arrives, and a shocking revelation follows: he is not just chasing the payroll—he is the brains behind the whole crime.
Fiske balks at the idea of Graham being murdered and dumped in the desert, and even suggests taking her with him. Blake, who is pulling the strings, rejects that plan and shoots Fiske in the back when he tries to escape. In a cold, calculating aside, Blake explains that his cover story will be that his late ex-partner, “apparently still at large,” will take the blame for the missing payroll. > "apparently still at large"
Determined to protect his own skin, Blake’s confession is deftly turned back on him by Halliday, who points out that if Blake removes him too, the army can still be convinced to return the stolen money and keep the $150,000 for Blake himself. Alarmed, Seton seizes Blake and disarms him as Graham creates a distraction, allowing Halliday to leap Blake and land a hard-fought confrontation. Graham’s quick action also leaves Seton wounded in the ensuing struggle over the weapon, and Ortega is summoned to seal the arrests.
With Blake cleared of wrongdoing by Ortega, Halliday is free to return to his unit. Yet, as they stand in the tense quiet after the dust settles, Graham hints that there might be a future for them in a different kind of life. She directs his gaze toward a passing Mexican couple boasting seven children, and Halliday understands her suggestion perfectly, a wry smile crossing his face as they contemplate what lies ahead beyond the border.
