A transformative year unfolds for Class 3-E at Kunugigaoka Junior High under the tutelage of the peculiar Koro-sensei. As alumni Nagisa Shiota and Karma Akabane revisit their alma mater, the echoes of that period resonate within them. The familiar surroundings trigger memories of their evolution into 'assassins,' meticulously nurtured for reality's challenges. Amidst the classroom's nostalgic elements, like desks and the class album, they reflect on the legacy of their enigmatic teacher—a being likened to an octopus—who tasked them with an extraordinary mission: to terminate him before the academic year's end. Thus, within the strange yet extraordinary confines of the 'Assassination Classroom,' their destinies were shaped and their lives forever altered.