At Giyu Tomioka's urging, Tanjiro heads for Mt. Sagiri with his sister Nezuko who's been turned into a demon. During the night, Tanjiro catches the smell of blood from inside a temple. He enters, thinking that someone might be hurt, only to come upon a man-eating demon. When the demon attacks, Tanjiro manages to fight back with his hatchet, but the demon's strength is overwhelming. Just as the demon is about to finish him off, Tanjiro is saved by none other than.

The Demon Slayer Corps... An organization that's been hunting down demons since ancient times. Sakonji Urokodaki starts training Tanjiro for Final Selection, the test for joining the unit. Navigating a mountain riddled with booby traps, dry sword swings, waterfall immersion and breathing techniques... A year later, Urokodaki informs Tanjiro that he has nothing more to teach him, and gives him one last hurdle to overcome in front of a giant boulder.

Inside the house, where the rooms spin each time the tsuzumi is played, Tanjiro gets separated from Zenitsu Agatsuma. Without Tanjiro by his side, Zenitsu is overcome by fear and despair as he takes Shoichi through the house. Meanwhile, Tanjiro meets the master of the house, the tsuzumi-playing demon, and an odd-looking man wearing a boar’s head mask.

After waking up from his dream by cutting his own neck, Tanjiro battles Enmu, who is the source of all the turmoil on the train. Enmu appears to be getting pleasure from inflicting pain on the passengers, which only infuriates Tanjiro even more. Tanjiro succeeds in severing Enmu's head, only to discover that Enmu's body is fused with the Mugen Train itself. Tanjiro is backed into a corner, but a freshly-awakened Inosuke comes to assist him and...

Tanjiro continues the fight against Hantengu. Amidst all his injuries and the Superior Four's skill, will he be able to defeat him? As the battle draws to a close, the Demon Slayer Squad must race against time to end the fight before dawn.