When she was a student, Kotone had the ability to win the national swimming competition, so she was transferred to her alma mater as a teacher and served as an advisor to the swimming club.It used to be a prestigious school for swimming, but times have changed and the swimming club has weakened and is facing a crisis of survival.She was entrusted with rebuilding, but her enthusiasm for teaching was spinning and a big gap was created between her and the students...Gradually the groove deepens and turns into hatred, and the students plan something...