While the couple lives happily in a house, Nao, the wife, is troubled by a certain problem. She has stopped having sex with her husband. And then there is her father-in-law who lives with her and sexually harasses her. Nao turns a blind eye to his actions, thinking they are due to the loneliness of having lost his wife, but Nao's attitude makes her father-in-law's sexual harassment escalate. One day, Nao's sexual frustration finally reaches its limit, and she ends up masturbating in the bedroom, but her father-in-law is secretly watching her.