It was two demons named Tamayo and Yushiro who came to Tanjiro’s rescue. Using the “Eyeblind” spell, Tamayo guides Tanjiro and Nezuko to her house. There, through his conversation with Tamayo, Tanjiro learns that there is a way to return demons to human form. Just then, two demons in pursuit of Tanjiro locate the house and unleash a furious assault...

Tanjiro's next destination, according to his Kasugai Crow, is to the south-southeast. On the way, Tanjiro runs into his fellow Final Selection survivor, the swordsman Zenitsu Agatsuma. Tanjiro has a hard time dealing with Zenitsu's passive attitude as they head deep into the mountains. They encounter two children whose older brother was taken away right in front of their house. There, Zenitsu hears the sound of a tsuzumi ringing out from somewhere.

One of the Twelve Kizuki, a direct subordinate of Muzan Kibutsuji, is here somewhere. When Tanjiro slays the Mother Spider Demon of Mt. Natagumo, he learns that a demon who might hold the key to turning Nezuko back into a human is somewhere in this very forest. With the battered Inosuke in tow, he heads deeper into the forest. Meanwhile, Zenitsu trudges forlornly through the woods only to encounter a spider with a human face.

Seeing Tanjiro try to protect Nezuko even as he collapses triggers memories of Rui’s own past. Once a sickly boy, he became a demon after meeting Muzan Kibutsuji who gave him a share of his blood. But after he turns into a demon, his own parents try to kill him. Ever since then, he has been searching for a family. Seeking a bond that he can never hope to acquire...

After the battle is over, Tanjiro and Nezuko are taken to the Demon Slayer Corps headquarters. This is where the Hashira Meeting between the Corps leader, Ubuyashiki, and the Hashiras, the most powerful swordsmen in the Corps, is to be held. The Hashiras censure Tanjiro for violating the Demon Slayer Corps by protecting a demon. And then, the Wind Hashira, Sanemi Shinazugawa, raises his sword against Nezuko...

As Tanjiro and the others are devoted to their rehabilitation training, the absolute master of the demons, Muzan Kibutsuji, gathers the Lower Ranks of the Twelve Kizuki. The demons, too, are preparing to make their next move. As training draws to a close, Tanjiro has improved to the point where he can fight on equal terms with Kanao. Just then, he receives word of a new mission from his Kasugai Crow.

Tanjiro, Nezuko, Zenitsu and Inosuke join Rengoku on the Mugen Train. Having heard that there may be demons on the train, they are on high alert, but they find themselves falling into a slumber. Within his dream, Tanjiro is reunited with his long lost family. However, it is soon revealed that this is a trap set by Enmu (Lower One).

After the Mugen Train incident, Akaza visits Muzan Kibutsuji. Guided by a crow, Tanjiro Kamado heads off to the Rengoku residence to convey Kyojuro Rengoku's last messages to his father and little brother. Tanjiro's group return to the Butterfly Mansion.

After being told of Zenitsu’s disappearance and to leave the Entertainment District by Uzui, Tanjiro and Inosuke decide that they will rescue Zenitsu. That evening, Tanjiro picks up a scent of a demon, which leads him to Koinatsu Oiran being swallowed by Daki’s belt. With Uzui nowhere in sight, Tanjiro must face the Upper Six demon alone.

Uzui deflects all of Gyutaro's Blood Demon Art attacks, and despite getting pierced in the jaw, Tanjiro is able to slice off Gyutaro's head. Though wounded from head to toe, Zenitsu and Inosuke also behead Daki, and they succeed in decapitating both demons at the same time. Just when it seems as though they've defeated the Upper Six demons after a fierce struggle, Gyutaro unleashes his Blood Demon Art...