One day, Ryoko discovers that her husband has been cheating on her and runs away from home, staying at her best friend's house for a while. However, the only son of the family, Jun, is in the midst of puberty. Unlike his mother, Ryoko is glamorous and beautiful, exuding the sex appeal of an adult. Jun has always admired Ryoko, so there is no way he can contain his excitement in this situation... Jun indulges in masturbation in his room, remembering Ryoko's sexy body, when suddenly Ryoko appears and whispers... "Shall I take your virginity?"