I, Mashibahara Kumihiko, was assigned as a new teacher at my alma mater this year. On my first day, I saw my ex-girlfriend from my youth.

More than 20 years have passed since then, but her appearance has not changed. Was it a hallucination? I followed her and put my hand on the classroom door.

There she was, the daughter of my ex-girlfriend ,Doujou Manami. At that time, I had no idea that I would spend my "youth" with her.

[From official site]