1998 film by Hou Hsiao-Hsien

Two melancholic Hong Kong policemen fall in love: one with a mysterious underworld figure, the other with a beautiful and ethereal server at a late-night restaurant.

Two neighbors form a strong bond after both suspect extramarital activities of their spouses. However, they agree to keep their bond platonic so as not to commit similar wrongs.

Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst.