Yurine, who lost her husband at a young age, lives with her daughter and son-in-law. She gets along well with her daughter's husband, Junki, and lives a simple but happy life. One day, Yurine witnesses her daughter and Junki arguing about sex. It seems that her daughter doesn't like sex, and keeps refusing even when Junki asks her for it. Worried, Yurine talks to her daughter about it, but she doesn't listen to her. Then, by chance, she comes across Junki pleasuring himself. Surprised and upset, Yurine takes an unexpected action. "My responsibility as my daughter's mother is also my responsibility..." Yurine grabs Junki's penis. At first, it was only supposed to be a handjob... but then she gives him a blowjob... and then she even has sex... Yurine desperately resists Junki, who can't stop...