In Tokyo, a ruthless gang starts holding up U.S. ammunition trains, prepared to kill any of their own members wounded during a robbery. Down-at-heel ex-serviceman Eddie Spannier arrives from the States, apparently at the invitation of one such unfortunate. But Eddie isn't quite what he seems as he manages to make contact with Sandy Dawson, who is obviously running some sort of big operation, and his plan is helped by acquaintance with Mariko, the secret Japanese wife of the dead American.