Feng (Shawn Yue) is a former undercover cop whose post-assignment life has begun to rapidly disintegrate. Feng and former triad brother Fai (Sam Lee of Gen-X Cops) are caught using cocaine, and the ensuing melee leaves a police detective dead, with Fai fingered as the culprit. Fai must go on the run, but he no longer trusts Feng, who he believes may be leveraging their brotherhood for advancement in the police ranks.

Feng has no desire to see Fai caught, and begins a desperate search for him, leading to a confrontation with his bloodthirsty former gang, as well as a reunion with club girl Sandy (Monie Tung of Whispers and Moans), his girlfriend while undercover. With the cops hot on the trail, Feng has to find Fai fast, or both of their lives will be forfeit. Meanwhile, the discovery of a months-old corpse may prove to have some connection to both Feng and Fai.-http://www.lovehkfilm.com/reviews_2/undercover.htm