Ririko enjoys a happy marriage to a man with an adult son. Her husband cooperates with their efforts to conceive, but age has left him sexually restrained, and her body secretly craves more. When he leaves on an extended business trip, she begins living alone with her adult stepson Yusuke. He starts acting differently, closing the distance and touching her more often. Though confused, Ririko cannot bring herself to stop him, and their physical contact grows steadily bolder until he begins repeatedly fucking and creampieing her in the name of giving her a child.