Shinnin Kyonyuu Jokyoushi Nana ~Owaranai Kounai Ryoujoku~

Nana is a new teacher at Tenga school.
"Just keep away from Koga Masao. Don't ever try to talk to him, " It is what a male teacher said to her at the end of orientation held in her first day at the school. But she is filled with a sense of mission to reclaim him from a life of vice.

[From DLsite English]