Reina's husband is on a solo assignment overseas, so she's been living with her son, Shogo. Shogo's friend, Shinichi, is mature and notices Reina's beauty, saying, "Shogo's mother is still so beautiful." This makes Shinichi start to see Reina as a woman. Meanwhile, Reina, feeling lonely with her husband away, has made masturbation a daily ritual, which Shinichi witnesses.
