In the past, she was a cute younger sister who would say things like, ``When I grow up, I'll marry my brother!'' - Lately, Kotone has started avoiding me. - Well, I think he's probably a tsundere. - There's no way Kotone would hate me. - For some reason, I'm in a good mood and I'm on the phone with someone... - Well, I never thought I could have a boyfriend! - ? - Before my beloved younger sister became the property of a man who didn't know whose bones came from, my older brother became my first partner. - Together, we graduated from virginity.