Holo is an Ayanashi, vanquishers of the Ogres, death incarnate. On his quest to pursue the one-eyed man who killed his brother, a young girl who shares a history with Holo, Ayame, appears before him, bearing a question. "Hey, Holo. Do you still remember the promise you made back then?" What could this mysterious promise be...? And in preparation for an anticipated Ogre assault, Ayanashi from across the land congregate for a joint operation!