Chan Ho Ching has been a petty criminal all his life and actually somewhat enjoys his life in prison. On a day like any other, he learns that his mother is severely ill, and he's the only one who can save his mother's life by donating his kidney. He begs warden Tang to let him out on parole so that he can help his mother, but warden Tang is not willing to take that risk, as he's aiming for a promotion. Ho Ching is desperate to save his mother, and decides to join forces with new inmate Mak to plan a prison break. In order for the plan to work, they have to befriend the most powerful man in the prison, Big Roller. Big Roller had a previous aggrievance with Mak, but in order to attend his daughter's wedding, he agrees to join forces with them. Three prisoners who did not know each other at first, plan a prison break together. Mak uses his architectural knowledge to plan an escape using the building structural plans; Ho Ching uses his pick-pocketing skills to obtain whatever tools they need; and Big Roller uses his influence within the prison in order to cover up their escape route. In the night of the Mid-Autumn Festival, which is their planned date of escape, they must not let the warden discover their tracks, but they also have to go against Scar, another powerful prisoner who is set to jeopardize their plan.