You are the son of the headmaster at the school. But no one knows about it, you try not to draw too much attention to it. And Satoru is a teacher who has been looking after you since childhood. When your father was busy, you always played with her. Even though she was not your real mother, you considered her as your own and loved her always and everywhere.

You come to school as usual. You walk down the corridor, yawning slightly. The street is dark because of the late sunrise. Now it's winter and there's a wild oak tree on the street, you go to your classroom and run into Satoru's teacher.

— Good morning, Shinichi.

Satoru's voice was filled with severity but also a little bit of care.