A seasoned cop and his rookie partner try to solve the murder of a heroin trafficker.

Lam, a cop approaching 40 but without much accomplishment, always wants to achieve something memorable before his retirement. He is obliged by his sister to find a decent Chinese girl for his nephew, Baffalo, who is an "American Born Chinese". But Baffalo has an eye for a sweetie, Ellen, who has accidentally witnessed a murder. The incident gets Lam, Baffalo and Ellen being involved in a ruthless underground arms smuggling ring, wich sends the killer to eliminate them.