Yori and his sister, Iku, are twins. They used to be very close as children but now that they are in high school, Yori has become cold toward Iku. Iku is confused by Yori's attitude. Actually, the reason why Yori has been cold and avoiding her is because he is secretly in love with her. What will Yori do about this forbidden love? (Source: MyDramaList) ~~ Adapted from the manga "Boku wa Imouto ni Koi o Suru" (僕は妹に恋をする) by Aoki Kotomi (青木琴美).