江湖上，两大门派鹰爪门和蛇形门世代敌对，双方都想将对方彻底铲除。一个月黑风高的晚上，鹰爪门突击了蛇形门，蛇形门遭到血洗，只有长老白长天（袁小田 饰）侥幸逃出。白长天为了躲避鹰爪门的追杀，隐姓埋名于市井。 　　一日，白长天被市井无赖欺负，街上武馆的打杂简福（成龙 饰）帮白长天打发走了无赖们；随后，暴露了身份的白长天遭到鹰爪门伏击，幸得简福路遇相救才捡回一条命。白长天决定传授简福蛇形拳，聪明好学的简福在学习蛇形拳后加以创新，独创了蛇形刁手。鹰爪门再次找上门，简福为了师傅挺身而出。Jackie Chan is a boy who is used as a janitor at his kung-fu school. Jackie Chan can't fight and is always getting bullied by the teachers and pupils. One day an old man helps Jackie train in an art of kung-fu called the ' Snake's Fist '. Jackie doesn't get bullied again. Then Jacki creates his own style and mixes it with the Snake's Fist. His style is based on the movement and actions of a cat. One day the old man is in trouble by a man who does ' The Eagle's Claw' and Jackie helps the old man.