Yumi spent her days masturbating. Yumi had an extraordinary libido, and was far from satisfied with her married life. However, she could not take the risk of having an affair, so she had no choice but to indulge in masturbation day after day. Then, one day, when her sexual frustration finally reached its limit, Yumi found out by chance that her son was a virgin, and crossed the forbidden line and helped her son lose his virginity. However, her son, who was Yumi's bloodline, also had an extraordinary libido. After his first sexual experience, his desire went out of control, targeting Yumi...