Oshioki Gakuen Reijou Kousei Keikaku - Season 1

Shimohei Joutarou begins his duties at the school before the academic term commences. His early arrival leads him to uncover a secret involving students Mitsuki and Minami. He subsequently learns of Mahiru, the younger sister of Classics instructor Kuji Hinako, and her remarkable academic progress. This discovery prompts him to find evidence of Hinako's behind-the-scenes manipulations. Joutarou's assignment is to correct the behavior of the institution's rule-breaking students.