Assassination Classroom: 365 Days

This film serves as a sequel to the Assassination Classroom television series and carries the fuller title 365 Days' Time under director Seiji Kishi. Rather than tell a wholly new story, it revisits the main narrative, threading its highlights through the adult perspectives of Nagisa and Karma as they look back on their year with Korosensei and how he made them who they became.

A grown Nagisa climbs the mountain staircase to the Class 3-E building, now signposted as the old classroom, and finds the door open. Wandering inside, he discovers Karma already there, though only Isogai is supposed to hold the key. Karma, planning to prank the rest of their old classmates the next day, invites Nagisa to explore the place with him. Nagisa marvels that nothing has changed, and Karma reminds him they bought the entire mountain, his own idea, so that no one could ever trash it.

In the teachers' room they pause at Korosensei's old seat and turn up a book labeled for a 3-E reunion, which sends Nagisa spiraling into memories. They relive their first meeting with Korosensei after the Moon was partly destroyed, the mounting bounty that drew the class in, the long list of weaknesses Nagisa once recorded, Karma's shifting respect for their teacher, Nagisa's sense that his life had become a role-playing game as he wrestled with his talent for killing, and Kayano's confrontation with Korosensei over her sister Aguri Yukimura.

Nagisa muses that he is at peace with not having been the one to kill Korosensei, while Karma insists their paths differ because this was the classroom their teacher built. Before leaving, they take a final look around. Karma sketches Korosensei on the board, Nagisa finds the old class roster, and the two urge each other never to give up as teachers. Nagisa writes a line about meeting him again someday, they lock the door, pay their respects, and head home together.

As a compilation piece, the film is designed for viewers already familiar with the series, restaging its emotional turns through a nostalgic framing device rather than new events. It was promoted alongside the spin-off Koro-Sensei Q! and released with cover art pairing the adult Nagisa and Karma with their late teacher.