Я хочу сказать, что я не твой брат!

Рикуто unaware that his younger sibling Ayumi is actually a girl pretending to be a boy on her mother's orders. Rикуто's heart beats faster whenever he sees his "brother." Ayumi desperately wants to tell Rикуто the truth. Rикуто and Ayumi, with Ayumi dressed as a girl, begin attending a popular private academy. Rикуто soon realizes that his friends all have their own issues - Matsuri has forgotten how to be a girl, the well-mannered Mao dresses like a boy, and the shy Kimika wants to change her personality. Rикуто and Ayumi try to help them.