Five boys at the prestigious Hachimitsu Academy, a school with a strict and overwhelmingly female student body, find their lives turned upside down when their clandestine scheme to peek at the girls' bath is discovered. Led by the impulsive Kiyoshi, the group, including the perpetually hungry Gakuto, the muscle-bound Shingo, and the quiet Jo, are immediately sentenced to a bizarre form of punishment: enrollment in the school's notorious prison, a makeshift detention facility run by the sadistic and scantily clad Underground Student Council. Now, the boys must navigate a daily existence of torment and humiliation at the hands of their captors, all while plotting an escape to avoid a potentially far harsher fate. This raucous, absurdist comedy blends over-the-top ecchi humor with relentless physical comedy, creating a tense and hilarious battle of wills that tests their friendships, their dignity, and their very sanity.