脑筋灵活的古惑仔阿旦（张家辉饰）为人贪财，情义欠奉，视身边所有兄弟大佬如摇钱树，多年来只有一兄弟阿劲（彭敬慈饰）留在他的身边，两兄弟在江湖上胡混度日。一次因为贪玩整蛊对头大佬雷气（黄秋生饰），白白令雷损失百万，再加上阿旦吞了大哥豺狼昆（李耀明饰）二十万公款，两兄弟不经意中成为江湖通缉犯只有选择双双跑路。

Dan and King are small-time Triad members in Hong Kong. After an incident in which their practical joke ends up losing their Boss a huge sum of money, AND in which they steal hundreds of thousands of HK dollars from a rival boss, the two are forced to flee to Phuket, Thailand (because the alternate hideout, China, would be "too boring"). They live the high life in Thailand with their stolen money, partying and falling for two local girls. Soon, the two comically inept Triad bosses come after them, the two girls turn out to be a mute assassin and the girlfriend of one of the Bosses, they escape from organ-harvesting Thais, in typical HK screwball fashion.