警察阿卢（周润发 饰）于枪枝交易现场发现了一具女尸，跟一个小女孩嘉嘉。为了能顺利破案，他找到了死者妹妹阿歇（钟楚红 饰），刚开始阿歇对阿卢有莫明的恐惧，拒绝配合阿卢的工作，但后来见阿卢对嘉嘉的细心照顾，慢慢对他有了好感。此时阿歇的前夫阿隆回来要求阿歇与他复婚，因为阿歇已经爱上了阿卢，便拒绝了阿隆的要求。
Plot Summary:The police are staking out a Hong Kong flat, waiting to catch some major gun-dealers. While the suppliers are conducting their deal, they move in. Both buyers are killed in the gunfire, but not their young daughter. The suppliers escape, and as their ruthless boss covers his tracks, he goes after the girl, the only witness. They trace her to a safe house, but are killed in the ensuing gunfight.