A young father and his infant son are beset by forces of evil and corruption. They wander China, upholding their sense of honor and protecting the weak. When they are forced into combat, spectacular and hilarious fast-motion kung fu sequences follow. In the end, they must call on all of their abilities in a battle royale, to attempt to vanquish a supernatural man-monster or die trying.

In the late 1970s, Cockney crime boss Harold Shand, a gangster trying to become a legitimate property mogul, has big plans to get the American Mafia to bankroll his transformation of a derelict area of London into the possible venue for a future Olympic Games. However, a series of bombings targets his empire on the very weekend the Americans are in town. Shand is convinced there is a traitor in his organization, and sets out to eliminate the rat in typically ruthless fashion.