Momoko, a wife, has been married for three years and is living happily with her husband, Keita, who is five years younger than her. - One day, her father-in-law Tadanori, who had been living a retired life, suddenly arrived without any notice. - Tadanori, who had been keeping an eye on Momoko for some time, started making fun of Momoko when he saw her when Keita wasn't around. - Momoko is having a hard time conceiving a child, so Tadanori gropes her body while telling her that it's ``infertility treatment''. - Momoko's sensitive body reacts twitchingly even though she knows it's wrong.