SEIROU OPERA

Set in the Yoshiwara pleasure quarters during the Edo period of Japan. Akane, the daughter of a samurai family, has lost all of her living relatives and has to sell herself to a brothel. A courtesan of that brothel tells her to go attract a customer, and as a result she ends up getting involved with a strange man who asks the brothel to buy her freedom... — Description from AniList community (anilist.co).