In Kunugigaoka Junior High School, the lowest class of all - Class E-3, although the class for the "runts" of the school with the lowest grades, it is also a special class, it is an Assassination classroom, the teacher is an alien lifeform that the students have been instructed to assassinate but the catch is, not even the military can. But despite this he is one of the best and caring teachers they could ever have, catering to every single one of them individually.