Chan Siu Hong is a lawyer who goes into jail after hitting a vicious policeman. He's welcomed by the inmates because he convinces fellow inmates not to use violence to settle every dispute.

The setting is 1960s Hong Kong, and righteous reporter Ching On (Tony Leung Chiu-Wai) publishes an article exposing corruption in the police force. Unfortunately, he's framed for drug distribution and confesses to the charges when the corrupt cops threaten his family. Forced to undergo the rigorous hazing rites of all new inmates, On struggles to regain hope and rise above his situation. Meanwhile, On's loyal girlfriend (Pinky Cheung Man-Chi) is terrorized by the cops who put him away, and On faces new challenges, and even finds new allies, while stuck in prison.