Suki Na Ko Ni Kokuttara Futago No Imouto Ga Omake De TsuitekitaSuki na Ko ni Kokuttara Futago no Imouto ga Omake de Tsuitekita; When I Confessed to the Girl I Liked, Her Twin Sister Came Along as a Bonus; 好きな子に告ったら双子の妹がオマケでついてきた

On a summer afternoon, Nakaba Masaki suddenly confesses his feelings to his classmate Yuzuki Tsubasa, who happens to be alone with him in the classroom after school. He braces himself for the inevitable rejection but the answer he receives is nothing he could have imagined: Ill go out with you, if youre willing to date my twin sister too.