有“地狱倒霉鬼”之称的李加乘(张家辉 饰)出生二十多年来几乎诸事不顺,对人生失望已极的加乘再次周期性自杀,而这次失败的自杀却使他结识了新朋友何红申(黄伟文 饰),以及美丽的护士小姐夏天(王秀琳 饰)。加乘向夏天表达爱意,但同时又担心对方会因为自己而倒霉——李加乘的晦气太重以至于所有对他好、或是受他帮助的人也会连带走霉运。当加乘与夏天的哥哥——赌术高手春天(冯德伦 饰)相遇后,他的霉运却成为赌场上唱衰对手的不二法宝,春天与加乘搭档,将宿敌大口九的赌场生意连连逼退,大口九反戈一击,将加乘绑架又买通春天手下,誓要致二人于死地……Sing has mysterious "bad luck" powers, which bring misfortune to anyone around him, including his pal Stanley, and also the sweet, charming Summer. However, Summer's triad brother Spring takes Sing to Macau, where his bad luck messes with the odds, and allows the pair to make a bundle at the tables. It also attracts the attention of evil gangsters who want to use Sing to make some bucks, or at least deprive Spring and Sing of theirs.