In post-World War II Tokyo, an American crime ring operates under the guise of a security company. The ring, run by the cunning and ruthless mobster Sandy Dawson, recruits dishonorably discharged soldiers to carry out heists and other criminal activities. Dawson's tightly-knit gang is meticulous and efficient, creating a seamless facade that makes it difficult for law enforcement to infiltrate. When one of their operations goes awry and member Webber is killed, the military police are perplexed as no leads come forth. They enlist Eddie Spanier, an ex-soldier with a shady past, believing he might have connections to the gang.

Eddie arrives in Tokyo and starts ingratiating himself with Dawson and his crew, pretending to be seeking work. As Eddie navigates the criminal underworld, he builds a complex relationship with Mariko, Webber's Japanese widow, who becomes an unwitting pawn in his undercover mission. Suspicion among the gang members grows as Eddie's true motives slowly surface. His dangerous double life unravels in a tense atmosphere, setting the stage for a confrontation that threatens to expose the entire operation and reveal hidden loyalties.