Akogare no Mio-nee wa Boku no Ninshin Dorei

Kouhei lives with his older sister, Mio. She is more than a sister for him, actually he loves her. She also loves him, but it is forbidden to fall in love with each other. To cut off her love toward him, she becomes Yusuke's girlfriend. Kouhei can't forget her, and starts to stalk them. One night, Kouhei goes to pieces and rapes her... Since then, he starts to insult her, and she can't stop it...