Triad leader Roller and life-sentence inmate Scar maintain the balance of power as the bosses of the prison they're incarcerated at. Life at the prison gets disrupted by the arrival of new inmate Mak, who has run-ins with both Scar and Roller. With things going so badly for him in prison, Mak has no choice but to join in the breakout plot being hatched by Chan. However, Roller and Scar also end up being part of the plan!
Ho Sau, an undercover agent, has been working with Yau, a drug lord, for years, but his job and family are in trouble.
