Married for 20 years. Her husband has been working away from home for the past 5 years, and Ai lives with her son, Hideyuki. One day, feeling lonely without her husband, Ai ends up cheating on him, but Hideyuki sees her cheating. Hideyuki, who sees Ai as a woman and not as a mother, is shocked and confesses his feelings to her. Happy about her son's feelings, Ai ends up having a forbidden relationship with him.