An assassin trained as a ninja carries the code name M. Hayami is a yakuza boss and a divorced father who is not allowed to come near his young daughter Mutsumi from his ex-wife Kazuko. In the big port city of Yokohama, M targets Hayami, who has angered the president of his group.

Undercover cop Kikuchi teams up with the Okinawa local police to clean up the narcotics and prostitution underworld.

Detective Kikuchi is sent to Okinawa to investigate why a girl jumped from a window after shooting heroin. There, he encounters the usual assortment of addicts, dealers, pimps and sleazy American GIs.