The fight between Hong Kong police and drug traffickers. Chan, a police agent, sets up a complex stratagem to force boss Chun Tu to commit a mistake.

Inspired by American cinema, Jackie Chan puts his model to shame and delivers a hallucinating film, that he considers his best action movie. A matrix for the genre, producing 5 sequels, a spin-off and hundreds of more or less copycat movies, that invaded neighborhood theaters and videoclubs. Hanging from a bus, breaking windows or mowing down slums with an automobile, Jackie Chan's stunts have often been copied but never equalled and remain totally insane.