The chief of Sampo City Police Office, Seung-u, organizes a simulation of a bank robbery, but a by-the-book cop gets too caught up in the role playing in which the simulation doesn't go the way he had anticipated.
An eccentric but faithful mafia, Chi-sung is sent to prison for his part in a gang fight. But when his parents are attacked by a rival mob and his own people take no action, he realizes that a decade of loyalty towards the gang has become futile. Determined to confront his own boss, he finds a way to escape from prison with his fellow inmates. Meanwhile, his friend Joo-joong is given the task to stop Chi-sung, forcing him to choose between the bond of friendship and loyalty towards the gang.