Rei Kuruki has a peaceful and happy life with her mother, Hijiri Maihara, because her father often abused her mother, leading to their divorce when she was still young. One day, Rei returned home looking strange, but her mother thought this was just what young people go through. However, a nightmare began when Rei's first love, who he had broken up with long ago, secretly snuck into their home and started tying up the mother and daughter to continuously commit immoral acts as revenge for Rei having left him in the past...