Rio married a man much older than her and started a new life with her new family. Her husband had a son from a previous marriage, but over time, any resentment faded, and she thought they had built a relationship like brother and sister, where they could talk freely about anything. However, her stepson gradually began to see Rio not as "family" but as "another woman." With this delicate distance between them, Rio and her stepson spend a week alone together...