Flame Hashira Kyojuro Rengoku receives new orders: Travel to the Mugen Train, where over forty people have gone missing, and conduct an investigation. Leaving the Demon Slayer Corps Headquarters, he sets off on this new mission.

Kyojuro Rengoku heads to the Mugen Train to investigate the disappearance of over forty passengers and encounters a demon along the way. After saving the people attacked by the demon, he finally arrives at the Mugen Train. What lies ahead of him?

Trapped in Enmu's spell, Tanjiro, Zenitsu, Inosuke and Kyojuro fall closer and deeper into an eternal slumber. Faced with death, Tanjiro is forced to confront his demons to save them.

With Tanjiro successfully awakening from his dream, he confronts the demon responsible, Lower One Enmu. But the situation challenges Tanjiro's resolve when Enmu proves more powerful that any demon he's ever faced.

Tanjiro and Inosuke battle Lower One Enmu, the strongest demon they've faced yet. With his limitless attacks and a potent Blood Demon Art, Enmu proves to be an extremely powerful adversary, forcing the two to attack in a way they have never done before.

Together, Inosuke and Tanjiro successfully behead Enmu, and despite the demon's final attempt to kill the passengers, everyone aboard the Mugen Train is safe. Heavily injured, Tanjiro attempts to rest and heal. But in the calm after the battle, a new and even more powerful danger arrives, threatening everyone.

Flame Hashira Kyojuro Rengoku continues to fend off Upper Three Akaza and sustains fatal wounds in the process, while the demon heals his own wounds instantly. Tanjiro and Inosuke look on helplessly as Kyojuro is brought low by Akaza.