Yoko is a wife who has been married to a kind and serious husband for 15 years now, and is living an ordinary but happy marriage. The Sasagawa couple, who are not blessed with children, loved Yuta, the son of a single-parent family who lives next door, like a child. One day, Yoko drank a salivation at the conversation she heard from the bathroom where her husband and Yuta were walking in together like a parent and child. "Yuta's pussy has become so impressive! I guess he's 17cm tall!?" Yoko, who has been without sex for three years, has no choice but to overlook this conversation...