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 having taken part in the theft, Halliday has no choice but to pursue Fiske into Mexico. Along the way, he runs into Joan Graham (Jane Greer), who is after the $2000 she loaned to her boyfriend, Fiske. The two join forces, though they are not sure at first if they can trust each other. Fiske stays one step ahead of the couple, while they are in turn chased by Blake. When Halliday is knocked down trying to stop Fiske from getting away, he comes to the attention of Police Inspector General Ortega (Ramon Novarro). Halliday claims to be Blake (using identification he took from the captain after a brawl.) Ortega lets him go after Fiske, but keeps an eye on him. His suspicions are confirmed when the real Blake shows up at his office for help.