When a bullying teacher from Katou Kiri's past comes to Kaimei Academy, he harasses the Sket-dan. But will the bully's actions push Student Council member/trained ninja Katou over the edge?
My homeroom teacher is the one 
who secretly egged them on.
Y quien los incitó a atacarme, 
fue el mismo profesor.
Foi o meu professor quem 
os instigou a fazer isso.