Corrupt police inspector Chun (David Lam) has made himself the most powerful law enforcement officer in Hong Kong by staging high-profile arrests of the criminals and mobsters with whom he's in cahoots. The British authorities know Chun is a dirty cop but have not been able to infiltrate his inner circle. Enter fearless and incorruptible military policeman "Dragon Ma" Yun (Jackie Chan), who comes back to his hometown to pose as Chun's new right-hand man and take down both cops and criminals.