Prisoner Cain Burgess is being escorted by police to a hospital where he learns of his mother’s death. After seeing her corpse, he fights off the cops and escapes their custody. He then visits a private bar, entering it after attacking the bouncers. While having his drink, he overhears one of the patrons named Tune describe how an unknown assailant killed a fellow gangster named Rook. Cain intervenes with his laughter, only to invite the wrath of Tune, his fellow patrons and Bez, the bartender. Claiming himself to be a friend of Lincoln, the owner of the bar, he tells everyone he’d walk away after finishing his drink, but gets into a brawl, acquires a double-barreled shotgun and holds everyone hostage. Soon, Lincoln’s lieutenant Hyde arrives, recognizes Cain as Lincoln’s brother and is also held hostage. One of the patrons trying to intervene is shot in the kneecap by Cain, who blames Hyde and Lincoln for his condition. Cain then starts narrating that he got sent to the notorious London prison HMP Belmarsh and had to fight for survival in prison due to a £20,000 price put on his head.