A son, Kenichi, who lost his father and lives with his mother, Shinobu. One afternoon, Kenichi noticed that Shinobu was wearing a thong. "Why is my mother usually sober and has no shreds of sex appeal?" Kenichi, who pretended to go out and scouted the house, witnessed sex with her mother and her cheating partner! "Mother is an introverted woman! You betrayed me and the dead old man!" Kenichi's heart begins to experience complex emotions that he has never experienced before.
