Yumi was concerned about her shy son Yuu, but was relieved to learn that he had recently made a friend named Atsushi, an honor student. However, Atsushi approached Yuu with the intention of violating Yumi's voluptuous body and cuckolding her. Atsushi then attacks Yumi. Yumi thinks of her son and endures the humiliation. Atsushi's abuse gradually escalates...