When nude pictures of girls turn up on the school's noticeboard, everyone suspects the class outcast, Kenji. Only one girl, Atsuko, defends Kenji. He tells her if she REALLY wants to support him, she'll let him fuck her. And that shit actually works.
After defeating her archenemy a while ago, Asagi thought she could finally settle down. However, her archenemy resurrected herself after making a deal with a demon. She swears to get revenge on Asagi by hurting her and the people close to her. By hurting, we mean fucking.