Three students, Hoshino, Tachibana and Keiko travel to an ancient and mysterious Chinese city in search of a potion that gives eternal youth. But once they arrive, Hoshino is attacked by a half-invisible creature that separates him from his friends...

A woman calling herself Princess Oryu enters the woman's prison. She is Kasumi, the daughter of the famous magistrate, Ooka Echizen, who slowly after hearing each of the prisoner's stories begins to realize the mystery that lies behind what it could be a big conspiracy.