Kei married a man with a child and became a full-time housewife. Her son Makoto, who witnessed her mother's affair when she was young, became traumatized and distrusted women, and never opened her heart to her stepmother Kei. One day, she secretly washed her nocturnal pants in the bathroom. Since then, in order to teach her the splendor of the opposite sex who hates women, sex education with her body started.
