Five years after a plague wipes out nearly everyone in the village of Ootsuka, its three survivors, Shino Inuzuka, Sousuke Inukawa and the girl they call Hamaji, are living in isolation in a church. Shino carries Murasame, a living sword spirit sealed in his right arm that steps out of it as a black crow, and when the imperial church moves to seize the blade, the fragile peace the three built collapses. Their flight puts them in the path of Genpachi Inukai, a captain of the imperial military police who turns into a demon that devours the supernatural.