Hisae was a mother with loose moral values. Even in front of her son Kenichi, she often wore revealing clothes, and accidental upskirt views were an everyday occurrence. She frequently invited casual sex partners and drinking buddies home to have sex. Although she had divorced her husband several years earlier, and Kenichi had accepted this, one day he ended up secretly watching his mother having sex. Captivated by what he saw, he was overwhelmed by feelings of jealousy.