In Canton, the master of a kung fu school dies and his seemingly lazy and undeserving son, Fei-hong, inherits. In the British commercial sector, an opium den opens with the bribed approval of the city's weak mayor. A merciless Japanese swordsman is challenging and killing the best fighters from every kung fu school. Fei-hong, who has fallen in love with the foreign swordsman's sister, must rid the city of the opium den, face down the hired guns of the British, establish his moral and physical authority to run the school, and meet his lover's brother in a dual.