Nanaho, scheduled to graduate from university in spring, returned to her alma mater for teaching practice. But the school was shrouded in a bizarre atmosphere, with both teachers and students acting strangely, turning the campus into a veritable den of depravity. One day, after showing defiance toward grade supervisor Kitashima, she was deemed "inexperienced" by him and forcibly ordered to participate in night class instruction. Surrounded by students and filmed without consent, Nanaho could do nothing but obey. Soon, loan sharks who had lent money to Kitashima appeared on the scene, escalating the sexual nature of her "training." This twisted situation would bring a profound and irreversible change to Nanaho's life.