Neither a prestigious school nor a so-called "ladies' academy."

The protagonist is assigned to teach at a school with an obscure tradition, arriving out of season. As a new teacher, he begins to form deeper connections with the students and fellow teachers.

This school has a "Witch Legend" passed down among the students. Initially dismissing it as one of those common school mysteries, the protagonist is soon confronted with an incident: a student gets injured in what appears to be an occult-like setup. The culprit and motive remain unknown, and whispers of the school's legend resurfacing begin to spread.

The teachers try to downplay it as an excessive prank, but similar incidents keep occurring, seemingly mocking their attempts to control the situation.

Who could be behind this, and for what purpose? The protagonist starts his own investigation.
[From DLsite]