After his family was brutally murdered and his sister turned into a demon, Tanjiro Kamado's journey as a demon slayer began. Tanjiro and his comrades embark on a new mission aboard the Mugen Train, on track to despair.

Tanjiro Kamado, joined with Inosuke Hashibira, a boy raised by boars who wears a boar's head, and Zenitsu Agatsuma, a scared boy who reveals his true power when he sleeps, board the Infinity Train on a new mission with the Flame Pillar, Kyojuro Rengoku, to defeat a demon who has been tormenting the people and killing the demon slayers who oppose it!

Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train is a follow-up to the extremely popular TV series Kimetsu no Yaiba (2019) that premiered in April 2019 and was based on Koyoharu Gotouge's comic, which boasts over 100 million copies in circulation in Japan. Featuring animation production from revered animation studio [error], the story follows Tanjiro Kamado's journey as a demon slayer after his family is brutally murdered and his sister is turned into a demon. The film opens as Tanjiro and his comrades have completed their rehabilitation training at the Butterfly Mansion, and they arrive at their next mission on the Mugen Train, where over forty people have disappeared in a very short span of time. Tanjiro and Nezuko, along with Zenitsu and Inosuke, join one of the most powerful swordsmen of the Demon Slayer Corps, Flame Hashira Kyojuro Rengoku, to face the demon aboard the Mugen Train, on track to despair.