A mysterious creature destroys 70% of the moon and warns that Earth will be next if not stopped by March. It demands to become the homeroom teacher of 3rd grade E class at Kunugigaoka Junior High School, and the powerless government agrees.
Now known as Teacher Koro, the creature teaches a class of failing students, including Nagisa Shiota, while the government tasks them with assassinating him, offering a 10 billion yen reward.
