"You're erect, aren't you!" Yuusuke was bewildered by his mother Rieko, who was covering him and playing with his dick. But at the same time, he felt his own worthlessness. It's been three months since his father left. His mother, who had been trying to forget her loneliness with alcohol, finally started to do such a dirty thing that she would knock her son down. Yuusuke, who couldn't comfort his mother, decided it was a one-time mistake and accepted the forbidden relationship. But Rieko's body, which is too erotic, turned her kind son who thinks of his mother into a beast...