Ask anybody about Kim Doyeon, and they'd all agree that she's the prettiest girl in school. Ask anybody about Yoo Yeonjung, and... they'd probably have no idea who you were talking about. Except Sejeong. Sejeong would know, because she was Yeonjung's roommate. Sejeong would also gladly tell you that Yeonjung is an idiot and said idiot should stop hanging posters of Doyeon all over the house.