This novelization retells the Mugen Train movie in prose, following Tanjiro Kamado and his companions as they board the Mugen Train after their training at the Butterfly Mansion, investigating more than forty disappearances tied to the train. They team up with Kyojuro Rengoku, the Flame Hashira, to confront the demons responsible once the train reveals its true danger. Told across six chapters and a prologue, it follows the film's story beat for beat rather than adding new content.