The moon suddenly shrinks to 70% of its original size and becomes permanently crescent-shaped due to an unknown force. The students of E Class at Kunugigaoka Junior High School discover their teacher is behind this catastrophic event. The teacher, a mysterious and supportive entity, has issued a challenge to the Japanese government: save the Earth from destruction or face the end of the world. Armed with weapons that only harm their teacher, the students must find a way to defeat him before the school year ends, or summer break will be cancelled.
Ansatsu kyôshitsu
As the moon mysteriously shrinks to 70% of its original size and becomes permanently crescent-shaped, a group of students at Kunugigaoka Junior High School discovers that their teacher is behind the catastrophic event.
