Because of her parents divorce, Hirayama Hayaka is forced out of a private school into a industrial school. When she arrives, she finds out that she is the only female student in that school, because all of the other girls transferred out! Apart from the great disparity between the number of boys and girls, she finds out that gansters still exist in this part of town. A conflict had also started between her classmate Katou Yuuni, a motherlike boy, and the gangsters. One incident leads to another, and she hits the previous school gang leader (and accidently knocks him out)! Furthermore, whoever defeats the school gang leader will be crowned as the new one. What does that possibly mean? Hayaka is now the school gang leader?!