Oshioki: Gakuen Reijou Kousei Keikaku
Japanese title: 懲罰指導 ～学園令嬢更性計画～
Type: OVA
Episodes: 3
Source: Visual novel
Genres: Hentai
Studios: Studio 9 Maiami
Producers: MS Pictures
Duration: 17 min per ep
Rating: Rx - Hentai

My name is Shimohei Joutarou. There is a reason that I'm here, at my new place of work, despite the fact that the school year hasn't started.

On that first day, I almost immediately came across Mitsuki's and Minami's secret. I then heard about Mahiru, younger sister of Classics teacher Kuji Hinako, and the astonishing improvement of her grades. I then discover indications of Hinako's backdoor maneuverings.

Now, it is up to me to rehabilitate these students who break the rules.

(Source: translated and adapted from official site by Cranston)