Penguin Brothers(ペンギン☆ブラザーズpengin burazaazu) is a manga series by mangaka Ayumi Shiina. The story follows tomboy Hina on her mission to liberate her high school from its two dictators. These two leaders have split the student population into two opposing groups: Isshiki's followers wear a white uniform; Nishizaki's wear a black uniform. With the help of non-uniform wearer (a.k.a. Grey) Koshiba she sets out to overturn the whole school.