After losing her husband, Mizuki decided to live with her daughter and son-in-law. The couple warmly welcomed her, and the three of them began their new life together. As days passed, Mizuki quietly observed the couple's intimate moments, secretly watching them and indulging in her own pleasure. One day, her daughter went on a trip. While checking on her son-in-law, Mizuki discovered him masturbating alone. Pretending it was accidental, she made the decision to enter his room. Seeing his embarrassment, she gently smiled and whispered, "It's okay," offering to help him. Her warmth and tenderness stirred something deep within him.