In an unknown location, an unconscious and restrained Tanjiro lies in a stone garden. A Kakushi commands him to wake up, and he jolts up to see swordsmen before him. One of them speaks of his disappointment in seeing him, having heard a Demon Slayer traveling with a demon and believing they would be someone flamboyant. Another decides they should all put him on trial. A girl among them is stunned to see him protecting his demon sibling, amazed by their sibling love. When Tanjiro tries to ask who they are, the Kakushi pushes his head into the ground, telling him not to speak as he is in the presence of the Hashira. Confused at what a Hashira is, Shinobu, who is among them, tells him he is in the Demon Slayer Corps Headquarters and will now be put on trial.
Shinobu asks Tanjiro to explain his crime but is interrupted by the loud and proud Flame Hashira, Kyojuro Rengoku; he states it is a clear violation to protect a demon, and they are allowed to dispense justice. He is joined by the eccentric Sound Hashira and Tengen Uzui. He offers to decapitate Tanjiro "flamboyantly" and proclaims he will show "the most flamboyant blood spray you'll ever see."
Meanwhile, the Love Hashira, Mitsuri Kanroji, is hesitant to kill "such an adorable child" and is unwilling to act. Gyomei Himejima, the hulking Stone Hashira, instead sees him as pitiful and pitied that he was born. The Mist Hashira, on the other hand, Muichiro Tokito, is looking and wondering at the shape of a cloud in the sky, ignoring the situation.
When Tanjiro looks around the garden, the Kakushi asks him why he is ignoring the Hashira, stating they are the nine most powerful swordsmen in the Demon Slayer Corps. Gyomei decides they should kill him, and Kyojuro and Tengen join his decision. Tanjiro looks for Nezuko, Zenitsu, Inosuke, and Murata but is unable to see them. One Hashira instead wants to question Giyu; Tanjiro looks into the trees and sees someone who states he is annoyed at seeing him unrestrained, as Shinobu said that Giyu had violated the rules as well. He is the Serpent Hashira, the cold and harsh Obanai Iguro. Obanai asks how they can punish him and asks Giyu if he has anything to say to defend his actions.
Giyu, revealed as the Water Hashira, doesn't respond to Obanai's question. Shinobu, the insect Hashira herself, insists they can deal with him later since he willingly came along. Instead, she is curious about Tanjiro's story, wanting an explanation despite the apparent violation of the rules. She plainly asks him why he is traveling with a demon as a demon slayer. Though he is given ample time to explain, Tanjiro attempts to say who the demon is but then struggles to speak and breathe. Shinobu gives him medicated water to help with the pain; she asks him not to push himself as his wounds have not healed yet.
Tanjiro tells his story; the demon is his younger sister. A demon attacked his family when he was away, and Nezuko was transformed. Despite this, she has never devoured anyone. Obanai states that if she's family, then he will obviously defend her, but he doesn't believe his claims. Gyomei, upon hearing that she was transformed, adds that they must kill her too "so that she can be liberated." Tanjiro begs them to listen and explains that he became a swordsman to find a cure for Nezuko, adding that she has not devoured anyone for two years. Tengen retorts that his story lacks any flare, and if he is going to plead his case, he should spice it up a bit.
Tengen demands that he prove himself "with max flamboyance." Muichiro ignores them, instead looking and wondering about a bird he sees flying above him. However, Mitsuri is unsure if they can proceed, not believing "the master" is unaware of the situation and asking if they can act without his permission. Seeing them still unwilling to listen, Tanjiro claims she can fight alongside him in battle and protect people as a demon slayer. They are then joined by someone carrying Nezuko's box. He enjoys the tense situation and insults Tanjiro as "the moron demon slayer with a demon." The Wind Hashira, the aggressive and brash Sanemi Shinazugawa, bluntly asks what he is trying to do.
Kakushi begs him to put down the box, and Shinobu gets up, with Mitsuri seeing her as unusually angry. Shinobu asks him not to step out of line. Instead, Sanemi claims Tanjiro's statement about her fighting to protect humans is a "total delusion," manically drawing his sword and stabbing into the box, but he vanished from this place and lies on the tree unconsciously.
All the Hashiras saw this and couldn't grasp what was happening, so they became alert and drew their swords. Before they could search, they were interrupted by the master's arrival. A blind and sickly-looking man appears; guided by his two aides, he makes his way before the Hashira.
The master comments on the nice weather and says he is pleased they made it to their semi-annual meeting.
Sanemi woke up, checked his surroundings, and saw the master. He then sees the other Hashira bowing to the master. Sanemi eloquently offers him greetings, pleased about seeing him in good health and wishing good fortune through continual prayers, to which a dismayed Mitsuri mutters that she wanted to provide her own similar greetings to the Master. Sanemi asks him about Tanjiro, who is shocked to see him speak with formal vocabulary when he initially appears brutish. The Master apologizes to them for the situation but unexpectedly reveals he has sanctioned Tanjiro and Nezuko's circumstances, adding that he would like them to accept it as well.
Gyomei states he cannot agree, despite knowing it is the master's intention. Tengen concurs with him, but Mitsuri quickly accepts his wishes. Muichiro states that he will likely forget either way, so he will be fine either way. Shinobu and Giyu remain silent, Obanai remains distrustful of the siblings, and Kyojuro exuberantly opposes the master's decision. Sanemi requests that both Tanjiro and Giyu be punished.
With his answers, the master asks for one of his aides to read a letter. She explained that this letter was given to her by a former Hashira, Sakonji Urokodaki. Reading the abridged version, the letter describes his wish for permission to be granted that would allow Tanjiro to be with Nezuko. Due to her resilient mental strength, she hasn't lost her human emotions. Nezuko has never devoured anyone for two years, even while injured.
Sakonji explains that in the aftermath of when she does attack someone, Tanjiro, himself, and Giyu will atone by committing seppuku. Tanjiro tears up when he sees Giyu after learning of his willingness and devotion to protecting Nezuko. Sanemi rejects their promise and states that they can die regardless, adding that it guarantees nothing. Kyojuro agrees and comments that her killing a human is irreversible.
Then a voice was heard from there behind: "Oh, and then what? Try to kill Nezuko to show your righteousness and silence his brother. You got a lot of nerve for a hashira." This caused all the Hashiras to become alert. There was somebody behind them all this time, but no one has been detected till now.
All the Hashiras surround Raja and are ready to fight, but Master, who is silent, raises his voice and objects to the way Nezuko is treated because she is a demon and should be killed without a trail.
Raja, stand up. "That's right, but the trail is for the wicked. If we check, she is the victim here, so she is free and has the right to live until she is found guilty."
Sanemi first reacts and asks, "Who are you, and are you the one who put me on the tree?" This question caused the remaining Hashiras to become highly alert.
The master, who is sielnt, started to introduce, "Children, reduce your hostilelity. Let me introduce you to your new acquaintance, Rudra Rajakumara, a disciple of my old friend, a demon slayer, and Kamado family Guardian brother."