The prison has been led by two powerful prisoners, who are triad leader Big Roller (Patrick Tam) and life imprisoned inmate Scar (Justin Cheung). The steady life in prison changes with the arrival of wrongly accused inmate Mak Kin-tin (Adam Pak).
First, Kin-tin was constantly being threatened by Scar, which led Kin-tin to give up on his appeal request and was later bullied by other inmates when they found out he was involved with destroying the storage unit with the belongings Big Roller’s presumed deceased daughter, when in actuality, Kin-tin was framed. In order to protect his life, Kin-tin takes the suggestion of his cellmate, Ho-ching (Louis Cheung), and they work together to plan a precise escape from prison.
In order to avoid the strict supervision of Warden Tang (Kenny Wong), Ho-ching persuades Big Roller to help them but informing him that his daughter is alive and they work together along with Kin-tin to devise an escape plan utilizing each one of their strengths. However, Scar also discovers the plan and the trio reluctantly let him join. As a result, these four inmates put aside past rivalry and work together to breakout of prison.