Their next destination is to the north-northwest. Tanjiro and Nezuko head towards Mount Natagumo with Zenitsu and Inosuke. This mountain is covered with spider webs and is swarming with innumerable spiders. Leaving the cowering Zenitsu behind, Tanjiro and Inosuke head up the mountain where they run into fellow Demon Slayers entangled in spider webs.

Flame Hashira Kyojuro Rengoku receives new orders: Travel to the Mugen Train, where over forty people have gone missing, and conduct an investigation. Leaving the Demon Slayer Corps Headquarters, he sets off on this new mission.

Nezuko, Zenitsu and Rengoku fight against Enmu to protect the passengers. Meanwhile, Tanjiro and Inosuke discover the location of Enmu's neck. They work in tandem to thwart Enmu's Blood Demon Art and sever Enmu's neck. The Mugen Train writhes in pain and derails. What will be the fate of the 200 or so passengers as well as Tanjiro and his friends?

The demon that appeared before Tanjiro and Rengoku after they defeated Enmu was the Upper Three, Akaza. While injured and on the ground, Tanjiro is almost attacked by Akaza and narrowly escapes death when Rengoku quickly strikes back. During the intense battle between Rengoku and Akaza, Akaza suggests to Rengoku that he should also become a demon. Rengoku vehemently refuses Akaza's offer, but his injured body is exhausted and being pushed past its physical limits...

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.

As Tanjiro close in on the demon that has been preying upon the entertainment district. But even as he closes in, the others continue to follow their leads toward their query. Who will find the demon first? And will they be able to survive the confrontation when they do?

Tanjiro, Zenitsu and Inosuke have joined Uzui in battle. While Zenitsu and Inosuke take on Daki, Tanjiro and Uzui deal with Gyutaro; however, they struggle as the demons have the upper hand with their coordinated attacks. But thanks to Hinatsuru's help and some teamwork from Uzui, Tanjiro's blade finds its way towards Gyutaro's neck...

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...

An Upper Rank Demon has been defeated for the first time in a hundred years by Uzui, Tanjiro, and his comrades' effort. This news causes a ripple effect not only among the members of the Demon Slayer Corps, but also the Upper Rank Demons, who have been summoned by Muzan Kibutsuji. Meanwhile, Tanjiro is recovering at the Butterfly Mansion when he discovers that he has upset his swordsmith Haganezuka after chipping his sword and decides to head to the village where the swordsmiths live to talk to him in person.

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.