The film opens with the Japanese military's failed attempt to capture anyone who destroyed half of the Moon, killing the entire team sent to capture it. Meanwhile, Nagisa Shiota, a ninth-grader at Kunugigaoka Middle School, recounts what kind of situation he was put into: he was put into Class 3-E, for those thugs and other school villains and is a joke in school. However, Class 3-E was actually a cover-up for the Japanese government in their attempt to kill Koro-sensei, a mutant whose tentacles were clearly the cause of Face's destruction. moon. Students must assassinate him before graduation using a special knife or BB pill, the moment he plans to destroy the Earth, but at the same time must also learn both academics and demons. close from him. In her teaching work, Koro-sensei was aided by the government's Tadaomi Karasuma and Irina Jelavić, a Serbian assassin.
Although fully aware that she is their ultimate goal, Koro-sensei is able to stick with Class 3-E, who always see him as their indispensable teacher. When asked why he took this job, he said that fulfilling his promise to someone was fulfilled. This term, Class 3-E welcomes three more students: Karma Akabane, who was recently suspended for protecting a former Class 3-E student from bullying by Class 3-A students. ; "Ritsu", an AI box displaying the shape of a girl; and Itona Horibe, the "biological brother", also had Koro-sensei's tentacles, who were taken away from the school by the cloaked guardian after losing a match with the latter. Once upon a time, Karasuma's P.E position. The teacher is briefly replaced by his rival, Akira Takaoka, a personal drill instructor. He is challenged by Karasuma, who successfully sends Nagisa to intimidate him, so expels him from school.