Troubled by their son's poor academic performance, his parents ask Mao Hamasaki, the wife of their friend, to be his private tutor. However, the moment the son sees Mao's alluring appearance, he stops focusing on studying and becomes consumed with lewd fantasies. Concerned, Mao desperately tries stricter teaching methods to improve his grades, but her approach includes increasingly erotic elements, causing the son to become even more of a pervert.