500 years ago, during their journey to the west to fetch the Buddhist scriptures, Monkey (Stephen Chow) got annoyed with the constant nagging of his master, Longevity Monk, and decided to betray him. He was intercepted and subdued by Guanyin, who decided to give him a second chance after Longevity Monk pleaded for leniency and sacrificed himself.<br /><br />Joker is the chief of a group of outlaws. Joker and his gang are attacked by two demons, Spider Woman and Bak Jing-jing, who threaten and force them to search nearby travelers for 3 dots on their feet, an indication of Monkey. Joker's second-in-command (a reincarnation of Pigsy) overhears the demons' plan to capture Longevity Monk and feast on his flesh to gain immortality, prompting Spider Woman to force him into servitude. Joker subsequently falls in love with Bak Jing-jing. Grandpa Buddha informs Joker about the danger he is in, gives him a magic mirror which can reveal a being's true form, and claims to the suspicious demons that Joker is a reincarnation of Monkey to give them time to escape.<br /><br /><br />話說孫悟空護送唐三藏去西天取經，半路卻和牛魔王合謀要殺害唐三藏，打傷紫霞仙子並搶走了月光寶盒。觀世音菩薩聞訊趕到，欲除掉孫悟空免得危害蒼生。唐三藏慈悲為懷，願以命相換，觀音遂令悟空五百年後投胎作人，贖其罪孽。<br /><br />五百年後，五嶽山下大漠風沙漫漫，斧頭幫來了一個奇怪的女客春三十娘。眾人在二當家帶領下欲行搶劫，反被她制住。匪頭至尊寶率眾復仇失敗，春三十娘勒令群匪找一個腳底有三顆痣的人。<br /><br />晚上至尊寶等欲用迷香加害春三十娘，卻令其現出蜘蛛精的真身。至尊寶孤身潛入春的房中，發現多了一個白晶晶，至尊寶對她一見鍾情。二當家夜探二女，查出原來春三十娘是蜘蛛精、白晶晶是白骨精，兩人得知唐三藏將會出現在五嶽山，這時牛魔王也得知唐三藏將會出現在五嶽山。二當家被春三十娘用移魂大法將其奴化。
