For Chiaki, her son Koji is everything, and the same goes for Koji. The two of them were close together in a single-parent household, and they had a strong bond. But before they knew it, their intense relationship had transformed into something only the two of them could understand... Wanting to have sex, Koji asked Chiaki to take his virginity. It was a natural thing for Koji, who believed that his mother would accept anything. And Chiaki didn't think it was abnormal.