After marrying her kind and serious husband for fifteen years, Yuko has led a happy yet ordinary married life. The Sakakawa couple, who have no children of their own, doted on Yuuta, the son of the single mother living next door, like he was their own child. One day, Yuko swallowed hard as she overheard a conversation coming from the bathroom where her husband and Yuuta were getting along like father and son. "Yuuta's thing is impressive, isn't it?! It must be at least 17 centimeters!" Unable to ignore this conversation, Yuko... who has been sexless for three years.
