Yuko who lives with her son, Ryota, who is a Ronin student, because her husband is away from home. Yuko had a bright and reliable personality and lived a peaceful life. It was Yuko who insisted that her husband, who is only serious, would not do such a thing. Yuko is immersed in masturbation so as to cancel out her uneasy feelings because she can't get in touch with her husband. At that time, Ryota notices something strange about his always cheerful mother.