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 to gather evidence that will prove Han's involvement in drug trafficking and prostitution. Shortly before his departure, Lee also learns that the man responsible for his sister's death, O'Hara, is working as Han's bodyguard on the island. Also fighting in the competition are Roper, an indebted gambling addict, and fellow Vietnam war veteran Williams.