Tony Leung stars as Yiu, who has been jailed for manslaughter. Chow Yun Fat stars as Ching, another prisoner also jailed for manslaughter. Ching is a good-natured prisoner who tries to make the best of his situation, and helps naive Yiu out.
It's a familiar story of the savagery of prison life, as Yiu & Ching must deal with intra-prison triads and a sadistic warden.
The pressure of these elements pushes them to the edge, and by the end of the movie, Ching & Yiu completely lose it. This is a very violent and uncomfortable movie to watch. The storyline doesn't make any profound social observations. But Chow Yun Fat's acting is very intense: he really turns into a bug-eyed wild animal. And Tony Leung is good as a man who would easily fall apart in such an environment if not for Ching's support.
The movie also has other Ringo Lam regulars like Tommy Wong & Roy Cheung (playing Billy & Officer Hung, respectively.)