Mugen Train Arc
Flame Hashira Kyojuro Rengoku is tasked with finding an elusive demon rampaging through a city. Believing that the demon Mugen is connected to the forty-plus disappearances on the train, he sets out to find and kill him.
Tanjiro, Genitsu and Inosuke Mugen meet Kyojuro on the train. After Hashira explains the situation, they discover two monsters hidden on board and witness Kyojuro’s impressive abilities firsthand.
While the demon slayers are asleep, Enmu instructs the four vulnerable travelers to tie their wrists, fall asleep, and enter their dreams. Armed with a smith made of his bone, they must discover his spiritual origin and destroy it to destroy them.
Tanjiro’s intruder finds himself in Tanjiro’s subconscious. The images of his soul take him to the spiritual center but he relents, not wanting to harm such a pure hearted soul. Tanjiro wakes up to find his comrades fast asleep.
Innosuke and Tanjiro attempt to battle Enmu from inside the train but find their attacks futile with his regeneration. Nezuko joins the fight and is nearly overwhelmed until Zenitsu arrives. Kyojuro finally joins the fray and deals enough damage to Enmu to stop his attack.
After the train derails, Enmu is distraught. Tanjiro struggles with his wound but manages to stabilize it under Kyojuro’s guidance. They meet Upper Rank Three, Akaza, who tries to persuade Kyojuro to turn into a demon, gain immortality and reach a higher power, realizing how powerful he was.
With what is left of him, Kyojuro launches one last, powerful attack at Akaza, momentarily stunning him. However, Akaza mortally wounds him, and flees upon seeing the arrival of dawn. In a desperate fury, Tanjiro slashes his sword with all his might at Akaza, who nevertheless runs away as Tanjiro, in a fit of rage, condemns him as a coward for running away.
Entertainment District Arc
Akaza meets Muzan, now disguised as a young boy, who vents his frustration at Akaza for not being able to kill the other three Demon Slayers besides Kyojuro. Akaza vows to kill Tanjiro as the latter visits Kyojuro’s brother Senjuro and his father.
To investigate the suspected demonic presence in Yoshiwara, Tengen sent three of his wives to infiltrate the three largest court houses in the district. However, he has started worrying about his safety as he has stopped receiving his messages.
Inosuke investigates a room he believes to be Makio’s, expecting to encounter a demon, but finds the room in disarray and empty. However, he quickly senses something moving through the ceiling and walls, and begins to give chase, though to no avail.
Tanjiro and Inosuke meet to exchange information, but their conversation is interrupted by Tengen. Upon realizing Zenitsu is missing, Tengen dismisses Tanjiro and Innosuke, not wanting them to risk their lives for his needs.