Nanba Prison is the world's most formidable fortress, designed to hold the most uncontainable criminals. Among its inhabitants are the four inmates of Cell 13: Jyugo, an escape specialist who seeks to find the man who put shackles on his limbs; Uno, a gambler with uncanny intuition; Rock, a brawler who just wants to eat good food; and Nico, an otaku whose body reacts strangely to drugs. Together, they turn prison life into a high-stakes, neon-colored comedy, constantly pranking their stern supervisor, Hajime Sugoroku. However, beneath the sparkles and jokes lies a darker mystery involving illegal human experimentation and the "Man with the Scar" who changed Jyugo’s life forever.