Yuna and Mizuki are good friends who are mothers. One day, while having a tea party as usual, the topic turned to sex life. Young Mizuki seems to be having fulfilling sex with a young man she met on an app... Yuna refuses the app, saying that having an affair is shameless, but she is swept away by Mizuki's momentum and starts using the app "just once"... Yuzuru, whom she met on the app, is obedient and submissive. Yuna awakens to the pleasure of dominating, something she cannot experience in her boring housewife life, and she drowns Kokoro and body in the swamp of matching.