Man Wanted (1995)

Original title: 旺角的天空

If you're an Undercover Cop, you go deep...or you get DEAD

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.