货车司机黄家驹（成龙）赴美向移居美国的骠叔祝贺新婚之喜，知晓其打算婚后与黑人妻子过安静的晚年生活，经营多年的超级市场也已卖给了年轻寡妇Elaine（梅艳芳）经营。由于一见面就对Elaine有好感，黄家驹主动协助Elaine打点起业务来。 　　不久，以Johnny为首的一帮朋克党开始恶意捣乱破坏超市，面对他们，黄家驹面无惧色勇敢地用起了自己的拳头，同时不忘晓他们以人生大义，然而这波未平那波又起，黄家驹又被卷入了钻石赃物被盗的漩涡，受到了黑手党的追杀。Keong comes from Hong Kong to visit New York for his uncle's wedding. His uncle runs a market in the Bronx and Keong offers to help out while Uncle is on his honeymoon. During his stay in the Bronx, Keong befriends a neighbor kid and beats up some neighborhood thugs who cause problems at the market. Meanwhile, one of those petty thugs in the local gang stumbles into a criminal situation way over his head. Blinded by greed, his involvement draws his gang, the kid, Keong, and the whole neighborhood into a deadly crossfire. When the lazy cops fail to successfully resolve matters, Keong takes things into his own hands. Needless to say, much spectacular kung-fu and outrageous action sequences follow....