For Chiaki, his son Koji was everything, and so was Koji. The two who lived together in a single-mother family had a strong bond. However, the relationship that was too close had been transformed into something that only two people could understand ... Koji who wants to have sex asks Chiaki to write down. It was quite natural for Koji, who believes that his mother will accept anything. And Chiaki didn't think it was abnormal either.