珠宝店售货员谢菲（陈百祥 饰）储蓄多年私己钻石，原欲卖掉用作与女友婷婷（李嘉欣 饰）结婚之用，不幸被劫去。婷父（胡枫 饰）知悉后便取消婚事。谢好友鲩鱼生（单立文 饰）常向谢借钱，而珠宝店老板是其舅父。生欠贵利债，两人各陷困境，一日无意中发现有人欲打劫珠宝，原来是老板与保险经纪合谋骗取七十保险金，这笔款项原属谢，谢大怒之下设下起尾注之计划……

Fred is a dopey jewelry company employee due to wed the impossibly pretty Tina. But Fred's stash of diamonds is stolen, leaving him with no feasible dowry with which to please Tina's tough dad. To replenish his depleted funds, Fred schemes with smarmy buddy Seng to steal some diamonds from his own company. But the plan doesn't exactly go as intended, and soon a gang of robbers, the cops, and even Tina's dad all seem to be after Fred and Seng! Can Fred win over Tina's dad, clear his name, and still marry the impossibly pretty Tina?