Hong Kong circa 1973. Lee, a member of a Shaolin Temple, is a master of the physical and spiritual disciplines of the martial arts, and is being visited by Braithwaite, a British law officer. Lee has been invited to a tri-annual martial arts tournament held on an island owned by Han, a reclusive billionaire who was once a member of the Temple but has now become a renegade. Braithwaite believes Han uses his tournaments as cover for narcotic and prostitution activities. Lee reluctantly agrees to enter the tournament, but his reluctance to confront Han disappears when a Shaolin monk reveals that during the previous staging of this tournament, he and Lee's sister were accosted by several toughs led by Han's personal bodyguard, an American named O'Hara. In the ensuing confrontation the monk cut a deep scar on O'Hara's face but Lee's sister ultimately perished, and at her gravesite Lee vowes revenge for her death. Also attending the tournament are two American martial arts experts, John Roper and Kelly Williams, who served together in Vietnam and took differing paths toward martial arts upon their discharge - Roper is on the run from Mafia gambling debt collectors, while Williams was accosted by two racist cops whom he'd dispatched before stealing their car to escape. All three will soon find themselves at the mercy of Han and his army of martial arts fighters as he protects his underground factory of narcotics and prostitution.