I Don't Like You At All, Big Brother!! #1

Plot

High school sophomore Takanashi Nao has a problem: she has a crush on her dreamy (if slightly pervy) older brother, Shuusuke. Fortunately, when Nao discovers that she was adopted as a child and they're not actually related by blood, it seems like the coast is clear -- but Shuusuke just doesn't see it that way. To make matters worse, Nao soon finds herself in direct competition with Shuusuke's hot childhood friend, Iroha. As the two girls vie for Shuusuke's attention, Nao soon learns that all is fair in love and war!