Koryu heads to Yokohama in search of a woman named Birei, kidnapped by diamond smugglers who move their hot rocks by surgically implanting them into the nubile buttocks of Chinese prostitutes. Koryu's older sister, working as a jewelry designer, is secretly, if unhappily, involved with the gangsters.

Martial artist Takuma Tsurugi returns to take on a Yakuza family that may be embezzling money from charities to finance their own operations. Both the police and the Yakuza find themselves battling Tsurugi, but Tsurugi's fight ultimately is with the mob, and he concentrates on them.