After finishing the study at the Butterfly Estate, Tanjiro reached the next place “Mugen Train” for task with friends. In a short time, over 40 people disappeared there and the Demon Slayers sent there all lost contact. Tanjiro, Zenitsu, Inosuke and Nezuko joined Rengoku Kyojuro, who is one of the “Pillars” of the Demon Slayers. They’re going to face the Demons hiding in the Mugen Train to the darkness....