Former warden Tang is imprisoned for accepting bribes, while Jun who failed to escape from prison returns to prison to continue serving his sentence. Jun sees that Tang is familiar with the prison and lures him into cooperating in the breakout plan. The two hit it off, and even tried to create trouble and blame it on Big Roller. Jun soon discovers that Tang has other tricks, forcing him to team up again with Big Roller, Mak and new warden Ma to crack Tang`s conspiracy.
Ho Chun, a young entrepreneur, is sent to jail. By implementing his philosophy in the business world that money can solve any problems, Ho Chun offers Big Roller, Kin-Tin, Scar and Ho-Ching a considerable amount of money for assisting him to breakout from jail.
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!
Liu Yue Ping reports to the ICAC about a rich 2G Cao Yuen Yuen who bribed officers of the Hong Kong Correctional Services (HKCS) from inside the prison. William Luk decides to infiltrate the prison as an inmate to conduct his investigation, while his partner Ching Tak Ming and Chief Inspector Lau Po-keung back him up from the outside.
A police detective must solve a brutal murder to prove his partner's innocence and unearth the truth behind Hong Kong's police force. The investigation brings him to an unlikely collaboration with an inspector from the Narcotics Bureau, whose motives may not be what they seem.
