In 1955 Japan, Mario Minakami, a new arrival at Shounan Special Reform School, finds himself in a cell with five other troubled teens, all facing serious criminal charges. Their encounter with Rokurouta Sakuragi, an ex-boxer inmate, sparks a deep connection and a pact to reunite after their release. Guided by Rokurouta, the group finds a glimmer of hope in their bleak reality. Together, they confront the abuse and cruelty of Ishihara, a vengeful guard, and Sasaki, a twisted doctor. Enduring unimaginable hardships, the seven unite to endure their punishment, but uncertainty looms over the kind of future that awaits them beyond the prison walls.