You would think that having your sister as your homeroom teacher would be a good thing. Unfortunately for one boy, that is not the case at all. He's always late to school, often daydreams in class, and his grades have now dropped dangerously low. The reason for this is none other than his sister. No matter what she does, her mannerisms and wardrobe choices come off as provocative and erotic, resulting in her brother being unable to keep his eyes off her body. Now the time has come for her to take responsibility for her actions! [Written by MAL Rewrite]