Ikushima Yurara lives with her twin brother Teito and, together with him, does whatever she wants. They look like children, yet their malice belies their appearance—they spend their days mocking and toying with others. There are no inconveniences because they use wealthy people as patrons through blackmail.

Both of them intended to continue to lead such an amusing lifestyle, however... One day, Teito vanished, and all contact with him was lost. For Yurara, he was like half of her body, and so his disappearance left her perplexed.

And then, Yurara received a call from one of the patrons, Miyake Isao. "Come to my office if you want to know about Teito," he said. The invitation was obviously a trap, but there was no way she could just sit still. And so, Yurara entered her white and muddy days...

[Translated from the official site]