In the Old Capital once known as Tokyo, a town that since the Great Fall most would rather forget, strange and mysterious crimes are taking place with increasing momentum. These acts are beyond understanding and so are labeled Phantom Cases. They bring fear and terror to what people remain in the Old Capitol, trying to lead normal lives.
Only one person is not fooled by the evil underlying each crime and is unafraid to challenge it: Hyuga Mayuki, a boy detective who holds a power of insight that uncovers the path to the truth through these mysterious labyrinths.
However, even as he sees to the heart of each additional crime, he remains unaware of the mysteries abounding in his own home and in his own existence.