Ah Itoshi no Banchou-sama

A girl named Souka and her recently divorced mother relocate to begin anew. Souka leaves her private school and enrolls in a technical high school, where she is the only female student. On her first day, she witnesses chaotic scenes of boys fighting. A classmate named Yu tries to protect her from the school's gang leader, Bancho, but a struggle ensues. Souka intervenes by swinging her book bag and defeats the Bancho. Unbeknownst to her, defeating the leader makes her the new leader of her class. She must now decide whether to keep or give up this unexpected role.