Tanjiro, Nezuko, Zenitsu, and Inosuke board a train[N 1] to assist the Flame Hashira Kyōjurō Rengoku in his mission to hunt for a demon that has killed many demon slayers. Soon after boarding, all of them are enchanted and fall into a deep sleep. Enmu, Lower Rank One of the Twelve Kizuki, instructs four passengers, all suffering from severe insomnia, to enter the demon slayers' dreams and destroy their spiritual cores so that they can't wake up again. In exchange, Enmu will allow them a peaceful sleep.
During their sleep, Tanjiro and his companions have happy dreams. Tanjiro realizes that he is dreaming and tries to wake up, succeeding after a vision of his father instructs him to kill himself in the dream. At the same time, Nezuko uses her power to sever the intruders' connection, and awaken the passengers. In fear of Enmu, they attack Tanjiro, who knocks them out.
While Nezuko awakens the others, Tanjiro confronts Enmu, and in the ensuing battle, beheads him. However, Enmu does not die, and reveals that he fused his head with the train. Kyōjurō instructs Inosuke and Tanjiro to look for Enmu's neck while he, Nezuko, and Zenitsu stay behind to protect the other passengers. Tanjiro and Inosuke find Enmu's neckbone in the engine room and Tanjiro severs it, killing Enmu and stopping the train.
However, Akaza, the Upper Moon Three, appears soon after and attacks the demon slayers. Kyōjurō fights him alone, and is fatally wounded, although Akaza is forced to flee when the sun begins rising. Tanjiro angrily calls him a coward for running away and declares Kyōjurō the winner of the fight. Kyōjurō encourages Tanjiro and his friends, and dies. The Hashira and Demon Slayer Corps are informed of his death, while Tanjiro and the others mourn him.
