Ranmaru Shindo has been having strange dreams about a girl with a sword, and the dreams have become more frequent. He doesn't have time to worry about them though, for he has just graduated from the police academy, and joins a section of the police force called Tokki. To his surprise, he meets the girl he has been dreaming about. Her name is Sakura Rokujo, and she is a member of a secret division inside Tokki. Humans are being mass murdered, and viscous creatures have appeared. Everything is related to the Box of Dirge.