Keung (Jackie Chan), a former Hong Kong martial arts champion, comes to New York to attend the wedding of his Uncle Bill (Bill Tung) who introduces his new wife to him down at his supermarket. Keung gets a job with one of the workers, Elena. Bill's friend asks him to take care of his car, until later that night, a street gang starts a motorcycle race near his apartment. They are about to run over his friend's car until Keung jumps down and stops them. He soon starts a rivalry with the street gang when he drives them away from the supermarket that they were robbing and vandalizing. When a member of the street gang gets involved in an illegal diamond deal gone bad and steals the diamonds, the small-time gangsters become the victims of a much larger criminal syndicate, and Keung agrees to help them. Keung convinces the street gangsters to reform, then brings the big-time criminals to justice.