U.S. Army Captain Frank Dux, trained from his youth in the ways of ninjutsu by Senzo Tanaka, honors his mentor by taking the place of Tanaka's deceased son Shingo in the illegal martial-arts tournament Kumite in Hong Kong. Two Criminal Investigation ...

U.S. Army Captain Frank Dux, trained from his youth in the ways of ninjutsu by Senzo Tanaka, honors his mentor by taking the place of Tanaka's deceased son Shingo in the illegal martial-arts tournament Kumite in Hong Kong. Two Criminal Investigation Command (CID) officers, Helmer and Rawlins, are summoned to track down and arrest Dux for desertion. After arriving in Hong Kong, Dux befriends American fighter Ray Jackson and Victor Lin, who becomes the manager and liaison for Jackson and Dux. The two Americans and the defending Kumite champion Chong Li — a fighter with a savage streak — all make it through the first day of the Kumite. Dux earns the enmity of Li after breaking his record for the fastest knockout. Dux advances to the tournament final to face Li, who alienated the audience by killing his semifinal opponent.