痞子武松（许冠杰饰）前往阳谷县寻找家兄武大（吴孟达饰），到景阳冈上骗吃骗喝，却借着酒意误打死一只老虎。阳谷县人将武松簇拥回县，县太爷将他封为都头。另一边，潘金莲（毛舜筠饰）与武大两夫妻正商量着如何骗钱，将目标锁定有钱却白痴的西门大官人。他们二人找到王婆，开始设计一个精细的行骗计划，而此时武松上门寻找家兄，二人害怕武松搅乱计划，所以百般隐瞒......

Tiger fighter Wu Sung was originally a coward. But when he was drunk, he was extremely courageous. One time at Jingyang Gang, Wu Sung got drunk and killed a tiger. His fearless fight impressed Sung Jiang and Lao Zhishen. Wu Sang's brother Wu Dalang seemed to be an enmity with Pan Jinlian, but in fact they were a pair of swindler. Pan used her beauty to seduce men into bed and then Wu Dalangn would come in and blackmail the victim, asking for huge sum of money. They were very successful.......