The earth is threatened by a powerful creature who destroyed 70% of the moon with its power, rendering into the shape of crescent moon forever. This creature also claim that within a year he will also destroy earth. But, he offers mankind to chance to avert their fate. He want's to working as a homeroom teacher in class 3-E at Kunugigaoka Junior High School, and he's not only teaches his student regular subjects, but also the ways of assassination to kill him. The Japanese Government tasked the students to kill him and promises a reward of 10 billion Yen for the student who succeeded kill their teacher. However, this was almost an impossible task for them because this creature had an ability of moving at Mach 20. and he was the best teacher they ever had.
The opening song is "Seishun Satsubatsuron" by 3-nen E-gumi Utatan, and the ending song is "Hello, Shooting Star" by moumoon
