Tanjirou Kamado and his friends from the Demon Slayer Corps accompany Kyoujurou Rengoku, the Flame Hashira, to investigate a mysterious series of disappearances occurring inside a train. Little do they know that Enmu, one of the Twelve Kizuki, is also on board and has prepared a trap for them.

After a string of mysterious disappearances begin to plague a train, the Demon Slayer Corps' multiple attempts to remedy the problem prove fruitless. To prevent further casualties, the flame pillar, Kyoujurou Rengoku, takes it upon himself to eliminate the threat. Accompanying him are some of the Corps' most promising new blood: Tanjirou Kamado, Zenitsu Agatsuma, and Inosuke Hashibira, who all hope to witness the fiery feats of this model demon slayer firsthand. Unbeknownst to them, the demonic forces responsible for the disappearances have already put their sinister plan in motion. Under this demonic presence, the group must muster every ounce of their willpower and draw their swords to save all two hundred passengers onboard. Kimetsu no Yaiba Movie: Mugen Ressha-hen delves into the deepest corners of Tanjirou's mind, putting his resolve and commitment to duty to the test.

TV version of Kimetsu no Yaiba Movie: Mugen Ressha-hen. The series includes an all-new episode 1 featuring the day leading up to the events in the movie, plus re-edited 6 episodes featuring new scenes and music, for a total of 7 episodes.

A mysterious string of disappearances on a certain train has caught the attention of the Demon Slayer Corps, and they have sent one of their best to exterminate what can only be a demon responsible. However, the plan to board the Mugen Train is delayed by a lesser demon who is terrorizing the mechanics and targeting a kind, elderly woman and her granddaughter. Kyoujurou Rengoku, the Flame Pillar, must eliminate the threat before boarding the train. Sent to assist the Pillar, Tanjirou Kamado, Inosuke Hashibira, and Zenitsu Agatsuma enter the train prepared to fight. But their monstrous target already has a devious plan in store for them and the two hundred passengers: by delving deep into their consciousness, the demon intends to obliterate everyone in a stunning display of the power held by the Twelve Demon Moons.