In the vibrant backdrop of Hong Kong, a gentleman named Mr. Braithwaite attends a sparring competition where an impressive martial artist named Lee faces off against a significantly larger adversary, Sammo Kam-Bo Hung. With his remarkable skill, Lee triumphs, prompting applause from the audience after he performs a breathtaking flip over a line of monks.
Later, Braithwaite talks to Lee, who takes a moment to impart wisdom on harmony and control to a young student, emphasizing that one should not attack out of anger or ego, and teaching him the respectful art of bowing. Braithwaite shares an invitation extended to Lee for a grand martial arts tournament hosted on a secluded island by the elusive Han, a figure rumored to have illicit ties to both prostitution and heroin—though concrete evidence remains elusive. Although hesitating at first, Lee ultimately accepts the mission to infiltrate the tournament as a spy.
Before embarking on this journey, Lee consults the wise Old Man at his Shaolin temple, who recounts the tragic fate of Lee's sister, Su Lin. In a heartbreaking tale, the Old Man reveals that Su Lin valiantly fought off Han's henchmen but, in a moment of desperation, took her own life with a shard of glass rather than succumb to their brutality. Heartbroken yet focused, Lee is driven by a desire for vengeance—not only for Su Lin but to uphold the honor of Shaolin.
As Lee prepares to travel to Han's island, two intriguing characters join him: Roper, a charismatic playboy dodging mobsters, and Williams, a man with a troubled past who recently escaped from a police altercation in the U.S. During their boat journey, Lee and Roper make wagers on a praying mantis fight, further establishing their personalities and camaraderie.
Upon arrival at the island, the trio is greeted by a spectacle of martial arts enthusiasts training on grand courts. Later that evening, Han hosts a lavish banquet, showcasing several entrancing feats, including women skillfully darting fruits from the air. After dinner, Roper shows a keen interest in Tania, one of Han’s attendants, while Lee encounters Mei Ling, a spy also sent by Braithwaite. She informs Lee of the disappearances of young women on the island, igniting his concern.
Lee's clandestine explorations lead him to discover Han's disturbing underground heroin operation, further showcasing the depths of Han's menacing character. Tension escalates during the tournament, with Lee and Roper both succeeding in their matches, while Han's retribution unfolds as he brutally punishes several fighters for alleged disobediences.
As the tournament progresses, Williams finds himself in a precarious situation during a confrontation with Han, who reveals his brutality by fatally beating him. Roper watches in horror as his friend is killed and becomes embroiled in Han's sinister plans.
The film builds to a climactic confrontation where Lee must face Bolo, Han's fiercest fighter, and later Han himself, who engages Lee with a menacing clawed hand. Their ultimate battle becomes a true test of wit and skill as Lee devises a strategy against the cunning drug lord, culminating in an explosive final duel among mirrors that strips Han of any advantage.
With the dust settling and Roper recovering from the battle, the film closes on a haunting note with the image of Han's claw lodged in a table—an indelible reminder of the confrontations that took place on the island and the personal journeys each character has undergone.
