Nozomu, a third year in middle school, has an elder sister who is 2 years older than him, Hitomi. When he came home from school one day he found his elder sister being violated by his father-in-law. He saved her despite it being a dangerous situation. Hitomi’s att.i.tude completely changed afterwards. Obsessed by Nozomu (as one of the opposite s.e.x), she started to remove any woman who approached him one after another. As Nozomu tried to regain the everyday happiness he had from the days with his deceased father, Hitomi’s abnormal affection continued to escalate.