Golden Sand City is filled with brothels and casinos funded by drug lord Yim Kung Ho (evil Mr. Yem) and policed by the iron fist of his henchman Panther (Leopard Head). Vigilantes Inspector Big Dragon (Bruce Liang), Little Mouse, and Black Cat plan to bring Yum Kung Ho and his evil empire to its knees, but face fierce opposition in the deadly Panther, who has the stolen pearls sought after by Big Dragon and his new ally Mei Ling.

When a once infamous criminal decides to give up his lifestyle and return the many treasures he has stolen to their rightful owners; he is promptly murdered by his partners in crime. To avenge his death is his son, with the deadly "mantis fist".