帮派分子乐文华与大哥陆乘风纵横香港，风头正盛。是日，陆、乐二人于码头接货，不想被警察团团包围。乐文华亮明卧底身份要求陆乘风投降，后者却冲入大海不知死所……一年后，经历了复职、受伤、升职的乐文华已经习惯了警队生活，然而却在一次抓捕中偶遇了陆乘风的情人蓉蓉（钟丽缇 饰），出于对蓉蓉的愧疚和同情，乐文华答应随时陪在她左右，这使得他与女友的关系出现裂痕。而大难不死的陆乘风此时又突然出现，请求乐文华帮自己最后一个忙，以讨回应得安度余生。乐文华一念之差卷入了陆乘风的犯罪计划，在陆乘风的复仇与警方的抓捕中苦苦挣扎……

Undercover cop Lok Hwa takes two years to become the trusted lieutenant of rising Hong Kong drug lord, Feng. The night of the big bust, Feng's flaming car crashes spectacularly into the sea; Feng is presumed dead. Hwa returns to the force and to June, his patient girl friend. Also, to save Feng's lover Yung from a life of crime, Hwa gives her his pager number and promises to be there for her. A year later, Feng reappears, asking Hwa's aid with one last task before he returns to the mainland forever. Feeling sentimental, Hwa agrees to help and finds himself set up to take the fall in a drug war. June is in danger, too, and death awaits as Yung realizes it's Hwa she loves.

После того как полицейского под прикрытием разоблачают, ему приходится в одиночку бросить вызов жестокому боссу триады.