rui raised tatsuya on her own and got him into university, and before she knew it, she was in the year she would graduate from university and had also been accepted into a real estate company. she thought that this meant that her child-rearing was over. when she thought about that, she felt like there was a hole in her heart. when spring comes, tatsuya will be living alone in tokyo. when she was feeling lonely, tatsuya invited her on a hot spring trip. "i want to go on a graduation trip with my mother who got me into university." rui and tatsuya set off on a graduation trip for just the two of them…