Warning: Spoilers ahead.
The Hashira Tengen Uzui explains that Tanjiro, Inosuke and Zenitsu will go with him to the Red Light District. Inosuke and Tanjiro are both clueless, but Zenitsu’s definitely heard about this kind of place and what goes on there! Of course Zenitsu would know…
Uzui warns them that they better behave and follow his orders. They better treat him like a god! Inosuke accepts that he’s a god, but also calls himself the King of the Mountain. Zenitsu is the straight man in all this.
They get to Yoshiwara, the Red Light District. Uzui tells them to stay put in the carriage, but both Inosuke and Zenitsu jump off, excited by such an environment. It’s filled with lights and people at night! That’s why Uzui thinks this is a place where demons are doing nasty things.
Uzui teaches them about oirans. The highest level courtesan of a house.
At an inn, Uzui explains their mission. They’ll have to go undercover to infiltrate the district and find intel. His three wives, all kunoichi, named Suma, Makio, and Hinatsuru. Zenitsu originally thought Uzui was a creep who couldn’t get women, so he’s extremely pissed off to learn that Uzui has not one wife, but three! And they’re all hot, busty babes!
So anyways, Tanjiro, Inosuke and Zenitsu have to disguise themselves as young girls, named Sumiko, Inoko and Zenko, respectively. It’s hilarious, the make-up makes them look ugly! Somehow, they’re lucky enough to each be accepted by the houses they want to investigate.
Inosuke’s chaperone wipes off all his make-up when they get to the house. They actually don’t want his make-up. They realize he’s beautiful, so beautiful they think he really is a girl!
Zenitsu is enjoyed at his house because he’s amazing with a shamisen the first time he tries it.
Tanjiro wasn’t appreciated at first because of the scar on his head. But then he proves to be a diligent hard worker, who’s strong.
He hears rumors that Suma Oiran committed Ashinuke, running away without paying debts. Koinatsu Oiran says she was writing about committing Ashinuke in her diary. Tanjiro thinks this is an easy way for demons to get away with abducting women. Oh, and Tanjiro lies that he wants to know the rumors because Suma is his big sister. He’s terrible at lying.
Meanwhile, Inosuke overhears that Makio is sick in her room. In reality, we see her tied up, being tortured by a female demon who hasn’t fully been revealed!