方世玉（李连杰 饰）原是城中纨绔子弟，好打抱不平。一日，他闻说外省富豪雷老虎在次设下擂台，比武招亲，又听讲雷小姐貌美如花，遂前往比武招亲。当方世玉过赢准备打赢未来岳母李小环时，一阵风吹过，将台上坐着的小姐的盖头吹了起来，他发现竟是一名丑女时，马上故意认输，溜之大吉。 方世玉的母亲苗翠花（萧芳芳 饰）听说儿子擂台上败下阵，自觉颜面无光，于是化身方世玉的哥哥方大玉前往打擂，一举打败了李小环。岂料雷老虎当晚即派人来接方大玉成亲。世玉为救母亲，只有代替母亲前往雷家成亲。 母子两计划新婚之后趁回门的时候一起出逃，岂料方世玉的父亲方德回来了！This Hong Kong martial-arts extravaganza tells of evil emperors and true love. The secret Red Lotus Flower Society is committed to the overthrow of the evil Manchu Emperor and his minions. One of his Governors is sent on a mission to retrieve a list of members of that secret society. Meanwhile, Canton kung fu practitioner Fong Sai-Yuk falls in love with the beautiful daughter of a rich merchant, recently moved to Canton. Her father, in an attempt to gain influence in the region and thus improve his business, offers his daughter in marriage to the winner of a kung-fu contest. Some interesting gender role-reversals take place during a 'comedy of errors.'
