Seiji Hasumi is a 32-year-old teacher at private high school Shinko Academy. He’s well-liked by both his students and peers and manages to solve problems left and right. But one student, 17-year-old Reika Katagiri, has a sneaking suspicion something is wrong with him. It turns out Hasumi has extremely unorthodox methods of fixing problems. Worse yet, he’s a complete psychopath willing to murder anyone who gets in his way.