Since losing his father in his youth, Tatsuya and Hikari have been living together just the two of them. Tatsuya had come to love Hikari, who loved him dearly, as a woman. Unaware of these feelings, Tatsuya grew into an adult and was soon facing the age of employment. He didn't want to leave Hikari, but he also didn't want to betray her for letting him graduate… Meanwhile, Hikari was troubled by the fact that she had never done anything motherly at all, so she invited Tatsuya on a hot spring trip.
