In a matter of seconds, the night sky is transformed when the moon explodes into a permanent crescent. The governments of the world are confronted by a yellow tentacled monster that claims responsibility for the disaster and threatens to do the same to Earth in a year's time. To keep the creature under control, the government agrees to give it a teaching position at Kunugigaoka Junior High School. However, this puts Class 3-E in an impossible situation as they must assassinate the monster responsible for destroying the moon. Despite the fate of the world resting on their shoulders, the students have personal issues to deal with such as discrimination from teachers and classmates. They feel defeated and incapable of success against a creature that surpasses human abilities. However, Koro-sensei, the enigmatic teacher, educates them in assassination and academia, giving them the courage to take aim at their target: the greatest teacher the world has ever seen.
Ansatsu Kyoushitsu ranked 1st in the 2014 Kono Manga ga Sugoi! ranking in the male readers category, was named by Nippon Shuppan Hanbai as the best work of 2013 on the list "Book of the Year," and was nominated for the 2013 Manga Taishou Award, ranking 6th place, and the 19th Tezuka Osamu Annual Prize in 2015. The series has sold over 20 million copies as of 2016.A VOMIC version was broadcast in Sakiyomi Jan Bang! from January to June 2013; the series has received a fanbook, databook, spin-off manga, and an illustrated English language guidebook called Koro-tan; and a live-action film of the series was released in Japan on March 21, 2015, which opened at number 1 on the box office; a second film was released on March 25, 2016.The series has been published in English as Assassination Classroom by VIZ Media under the Shonen Jump Advanced imprint since December 2, 2014; in Italian by Panini Comics under the Planet Manga imprint since May 10, 2014; in Portuguese since July 2014 by Panini Comics and in Spanish by Panini Comics since October 2014.