Kyuuki, a strong and proud fox demon, has recently woke up from her lengthy slumber and requires a host to maintain her presence in the human world. After a decisive encounter with would-be attackers, a normal high school student named Shin Kamishiro is drawn into their conflict and subsequently gains possession of a powerful artifact that controls Kyuuki's existence known as the Black Grimoire. Shin is bound to this artifact as long as he remains alive. Thus, not only can't he sever his connection to Kyuuki, but he must also fend off other demons who vie for the power of the Black Grimoire.
Kyuuki is attacked by a high-class demon.
Kyuuki attempts to convince Shin that death is a preferable alternative to finding a non-lethal way of recovering the Black Grimoire.
With her existence discovered by the battle maiden Kurosaki, Kyuuki is captured through use of holy bindings.
Kyuuki runs away from home... and then returns.
Shin makes contact with the inner guardian of the Black Grimoire, Kuon.
After their first trial in joint combat, Kyuuki receives a curse that forces her into a child-like form. Not long afterward, during their counter-attack, Kurosaki is defeated and suffers from the humiliation of failing her mission.
Kyuuki engages and defeats the attacking demons.
Shin appears before Kuon once more, attempting to gather information on how to render their defeated opponents incapable of pursuing the Black Grimoire without killing them.