As the Big Three cliques of Tokiwadai Middle School ruthlessly compete with one another, a member of the Mikagami Clique is attacked! Tensions heighten to the point of developing into a skirmish. However, each of the clique leaders cannot help but feel something is off about the entire situation. Eventually, the repercussions reach all the way to the school's two Level 5's! Misaka's first-year arc comes to a tumultuous climax that brings in the entire student body of Tokiwadai Middle School!