Samuel Fuller directed and cowrote this typically hard-boiled drama set in Japan following World War II. Eddie Kenner (Robert Stack) is given a special assignment by the Army to get the inside story on Sandy Dawson (Robert Ryan), a former GI who has formed a gang of fellow servicemen and Japanese locals who use their muscle to take over Tokyo's pachinko racket and commit a series of train robberies, targeting deliveries of military ammunition.
Eddie is supposed to gather evidence on the murder of a soldier believed to have fallen in with the gang, and Eddie tries to blend in with the group to find out how they work.
Hoping to learn more, Eddie also begins romancing Mariko (Shirley Yamaguchi), a Japanese woman who was married to the slain gangster, and he learns that the ruthless Dawson kills men who are injured during robberies rather than leave them behind to possibly testify against him.
After a burglary goes wrong, Dawson becomes convinced that there's an informer in the group; wrongly believing it's Griff (Cameron Mitchell), Dawson kills his loyal soldier and makes Eddie his second in command. Veteran Japanese actor Sessue Hayakawa appears as Inspector Kito, a Japanese police detective working with Eddie to crack the case.