Six years after having been sentenced to life imprisonment for the massacre of her entire village, Shun Shutsuki is recruited by the master of Gushiken Paranormal Organization and taken out of prison. Shun is the possessor of the Godai Shakujō, a hereditary ability of the Shutsuki Clan, which appears only once in several generations and manifests itself in the form of a powerful anti-monster weapon. According to Kagami Gushiken, the master of the Organization, Shun wasn’t herself during the massacre; she was possessed by a demon. However, this does not appear to be the entire truth; only Doctor Tsunan Hitachiin and the Master seem to know exactly what happened that fateful night.
Evidently, the other members of the Organization are not at ease- to say the least- with the idea of having a “mass murderer” amongst them, with Tsunan’s fan-club being particularly averse to Shun’s presence within the organization. Even if monsters are absolutely real, none of them believe in the existence of demons and much less in demonic possession. Everything becomes complicated when Naoto Higaonna, an ex-member of the organization- who is now working as a high-school teacher- kills a group of students out of the blue before committing suicide. Things become even more complicated when the members of the Organization discover that Shun is constantly being hounded and persecuted by a certain Tadashi Honjō, with whom Shun seems to share a long-time bond. Who is Tadashi Honjō? Or rather, what is he? But, above it all, who is Subaru?
What is Shun hiding so desperately? Will she be able to survive within the Organization? Will she return safely from the missions assigned to her?
