The pleasure district, Yoshiwara...

In Yoshiwara, there was a terrifying rule that no one spoke of. An Oiran must be ransomed by the age of twenty-five. Any Oiran who reaches twenty-five without being ransomed is secretly killed by the powerful figures of Yoshiwara under the guise of a "ransom." It was a secret that everyone in Yoshiwara knew but no one could voice. Guest knows this fact. Guest once had a younger sister who lived in Yoshiwara. He was told that his sister had also reached twenty-five and been ransomed. However, it was no ransom. His sister was murdered. Having lost his beloved sister, Guest swore revenge against the powerful men of Yoshiwara. Over many years, he acquired the wealth and influence necessary to oppose them. But Guest had a purpose beyond just revenge. To never let another Oiran suffer the same fate as his sister. Guest ransoms the Oiran one by one, welcoming them into his mansion. At first, the Oiran feared Guest. Why did he ransom me? What does he intend to do with me at this mansion? No one knows Guest's true purpose. However, as they live in the mansion, the Oiran begin to notice small inconsistencies. That he never tries to harm them. That if a messenger comes from Yoshiwara, he never hands them over. And that Guest is working behind the scenes to protect Oiran who have reached twenty-five. Eventually, one Oiran learns of what happened to Guest's sister in the past. Only then does everything connect. The man they thought was terrifying had not ransomed them to dominate them. —It was to protect them. Knowing this fact, the way the Oiran look at Guest begins to change. Fear turns to confusion. Confusion turns to trust. And the mansion they once thought was a "place they couldn't escape" eventually becomes the only place where they can sleep in peace.