Nanba prison is notorious for housing the most elusive inmates in the world, with Cell 13 being home to four particularly skilled escape artists. These include Juugo, a seasoned prisoner with expertise in locks, Uno, a gambler with exceptional intuition, Nico, an otaku whose unusual physiology makes him resistant to drugs, and Rock, a large, food-loving inmate. As Hajime Sugoroku, the supervisor, struggles to keep them contained, the daily antics of these prisoners consistently disrupt the prison's operations. Despite its harsh reputation, life in Nanba proves surprisingly comfortable, with routines like three meals a day and sports festivals making it almost like a home for its inmates.