Mari, a friend of his mother, came to Tokyo to accompany her husband on work. Kazuya's son couldn't contain his excitement when he found out that the woman he admired was coming to stay for a few days. Meanwhile, Mari had been feeling a secret awkwardness ever since she had once witnessed him masturbating... She was moved by the sight of him growing into a strong young man, and using her drunkenness as an excuse to kiss him without thinking. Her body, which had forgotten about a man for years, felt a hot excitement from the contact after a long time, and even though she knew it was her friend's son, she crossed the line...