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.

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...

Hantengu's head is slashed by Muichiro and he splits into two clones. Muichiro is blown away by Karaku. Tanjiro, Nezuko and Genya are stunned when the clones split into more clones. Muichiro rescues Kotetsu from a Goldfish Demon.

Tokito continues advancing through the forest and finds Mr. Kanamori. As soon as they arrive at the work hut in the middle of the forest, they are welcomed by Gyokko. Meanwhile, Tanjiro continues his fight against Hantengu.

Two simultaneous fights continue, Tanjiro, Nezuko and Genya against Hantengu and Tokito against Gyokko. Genya began to show a demonic form. Tanjiro asks him to look for Hantengu's real body, but memories of the past begin to plague Genya.

Genya aims for the neck of the fifth demon that split off from Hantengu, but the demon's neck is shockingly hard, and his sword snaps in half in his attempt to strike it. His gun is also ineffective and Genya is driven into a corner. Realizing that he is unable to sever the neck by himself, he entrusts defeating the fifth demon, which is believed to be the main body, to Tanjiro. Taking on Genya's will, Tanjiro wields his sword against the fleeing demon...

Muichiro, with the help of air blown by Kotetsu to him, escapes Gyokko's Water Prison Pot. Muichiro finally recalls his tragic past.

Armed with his memories, Muichiro feels powerful and invincible, convinced that the demonic fifth moon has no chance against him.

Tanjiro, Nezuko, and Genya are struggling through an arduous battle against Zohakuten and his five tree dragons. They are forced to fight defensively against the tree dragons using the four emotion demon's powers, and Tanjiro is swallowed by one of them amidst the fight. Just as Tanjiro is close to meeting his demise, Mitsuri arrives in the nick of time and rescues him. And now, Mitsuri faces off against Zohakuten to rescue the captured Nezuko and Genya...!

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.