Nanba, known as the world's most secure prison, is designed to contain criminals who excel at escaping traditional jails. Within Cell 13 reside Juugo, a lock expert with a lengthy prison history; Uno, a skilled gambler with sharp instincts; Nico, an otaku with unique drug reactions; and Rock, a tough guy who adores food. These crafty inmates have baffled every other prison system with their flawless escape record. Their daily antics, much to the dismay of supervisor Hajime Sugoroku, constantly challenge the prison's security measures. Nanbaka humorously narrates the misadventures and glittering escapades of these inmates and their watchful guards. Despite the chaos they cause, life in Nanba offers the four a semblance of home, from regular meals to lively sports festivals.