Mayumi, an enthusiastic mother, teaches her son Takashi, who is not doing well in school, every day. One day, while studying, Mayumi notices an email from Takashi's friend and when she opens it, she finds a picture of a woman with big breasts... Mayumi believes that the reason her son's grades are not improving no matter how much he studies is because of the evil thoughts of adolescence, so she does everything she can to get rid of her son's lewd thoughts, but before she knows it, she is hooked on her son's penis...