Lee, a highly proficient Shaolin martial artist and instructor from Hong Kong, is approached by Braithwaite, a British intelligence agent investigating the suspected crime lord Han. Lee is persuaded to attend a high-profile martial arts competition on Han's private island in order to gather evidence that will prove Han's involvement in drug trafficking and prostitution. Shortly before his departure, Lee also learns that his sister's killer, O'Hara, is working as Han's bodyguard on the island. Also fighting in the competition are the indebted gambling addict Roper and fellow Vietnam war veteran Williams.