Yuriko is a very ordinary housewife. However, she has a secret that nobody knows about. That secret is that her son forced her into having sexual relations with him against her will. At first, Yuriko thought it was just once but her son didn't think so and kept pressuring her for more, eventually leading her to give in to his advances again and again. When she tried telling her husband about their son's behavior, he simply replied that he was tired and couldn't help her. Feeling frustrated and unable to release her pent-up emotions, Yuriko started masturbating but was caught by her own son...