Emi, a mother, worries about her son who is exhausted and depressed after a hard day at work. One day, Emi and her husband have sex at night, but her son peeks in and gets excited. Emi notices her son peeking, but pretends not to notice for the time being. The next day, Emi goes to her son's room. She tells him about the previous night, being careful. "You were hard, weren't you?" she asks, making up her mind and groping her son's crotch. To cheer her son up, she starts taking off her clothes, saying, "You can do whatever you want with my body." The son is confused, but he becomes excited and, guided by his mother, they make love...