In the outskirts of Tokyo lies Hachimitsu Private Academy, an esteemed all-girls boarding school known for its rigorous education and disciplined atmosphere. However, a significant change emerges as the school allows boys to enroll, leading to a unique ratio of two hundred girls to one boy. Five boys - Kiyoshi, Gakuto, Shingo, Andre, and Jo - find themselves isolated and unable to connect with their female peers. Determined to make an impact, they devise a risky plan to spy on the girls' bath, only to face the wrath of the Underground Student Council. Condemned to a month-long imprisonment within the school, the boys navigate a challenging journey in Prison School, where their unity and questionable camaraderie are put to the ultimate test.