姉妹教師 ～恥辱の時間割～

On the surface, our hero is just an ordinary student at Seijo High School. However, he is actually a sadist, who gets his kicks out of violating women. He's already attacked several girls. His next target is a beautiful teacher, Reiko Watase. He takes pictures of her as he rapes her. He then uses the pictures by threatening to use them against her. He forces her to sign a contract that says, "Every time she obeys an order, he will return one picture to her." Reiko's little sister arrives at the school as an intern. Our hero starts to eye Miyuki Otonashi as well...

[From Gamelex]