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.

Enraged by Daki's contempt for human life, Tanjiro attacks her with more intensity and gradually corners the demon. But he's already gone past his physical limit. As Tanjiro collapses and all seems lost again, Nezuko appears. A vicious battle ensues and Nezuko starts transforming into a more demon-like form...

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...

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 intervenes during an argument between a pillar and an apprentice blacksmith and learns of the existence of an amazing training method.

Tanjiro begins his training with Yoriichi Type Zero and is pushed to the limits by Kotetsu's relentless coaching and extreme training. Through this experience, Tanjiro masters a new skill of predicting where the opponent's next move will hit by using his sense of smell. During his training, Tanjiro lands a blow on Yoriichi Type Zero and ends up destroying it, but a sword from over 300 years ago appears from inside...

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.