Yori and Iku are twin brother and sister. Their parents mostly work hard for their best education. Mostly Yori, Iku's brother, has good intelligence and looks. And as for Iku well... Iku's character is kind of a kid one she mostly acts like a kid towards Yori and her parents but she has a cute face. Iku and Yori had been together since childhood they've been together their whole lives. But lately Yori acts differently.. he gives Iku the cold shoulder and gets mad at her is as if he wants to be apart from her. Iku worries and thinks that her brother Yori hates her. But the real truth about Yori's doing's are far more being a "Big Brother" to sweet little Iku. Now, Yori risks different things anything and everything to have Iku. Iku loves her big brother Yori enough that she would risk losing him and she'll do what it takes to keep them together. But Yori doesn't want her that way towards him... as a loyal twin sister dedicated to her own twin. Is it possible that Iku will love Yori not as her big brother but as a man? From ShoujoMagic: Yori's attitude has changed. He and his twin sister, Iku, used to be inseparable as children, but lately Yori's been different -- eager to be apart from Iku. Iku worries that he hates her, but the truth is far more scandalous. Now, Yori would risk losing everything to have his little sister. Iku loves her big brother enough that she would never risk losing him, and so she'll do what it takes to keep them together... but Yori doesn't want to have her that way -- as a sister dedicated to her twin. Can Iku ever love Yori not as a brother but as a man? Boku wa Imouto ni Koiwosuru received the Shogakukan Manga Award for sh?jo manga in 2008.