导火线

重案组沙展马军（甄子丹 饰）致力抓拿犯罪分子，身手不凡的他由于抓贼心切常常出手过重。警方一直搜集越南帮兄弟阿渣（吕良伟 饰）、Tony（邹兆龙 饰）、阿虎（行宇 饰）的犯罪证据，于是派出了华生（古天乐 饰）以卧底的身份潜入他们之间。三兄弟为人心狠手辣，想铲除掉眼中钉阿山。阿渣被抓后，Tony也识破了华生的真实身份，要将华生以及其他证人通通杀掉，救出大哥。华生女友秋堤（范冰冰 饰）被挟持，华生不得不放弃指证阿渣。华生与女友都抓走当人质，马军也带着阿渣去营救华生。Ma Jun, a cop known for dispensing justice during arrests, teams with Hua Sheng, who's undercover, to try to bring down three merciless Vietnamese brothers running a smuggling ring in the months before the mainland's takeover of Hong Kong. The eldest, Xian Wei Cha (called Zah), is arrested in an operation that exposes Sheng and almost gets him killed. His girlfriend, Qiu Di, who's been unaware of Sheng's profession, wants to see him quit. Jun pursues the gang tirelessly, sometimes ignoring police protocols. Zah's trial approaches, witnesses are in danger, and a showdown is inevitable.