God exists and is dormant in the depths of the human unconscious. He has known all the fears of the world through a nightmare and became omniscient. But the human mind cannot bear all these horrors, which, mixed with the terror of men, emerge in reality, in the form of fragments. To protect the world from these fragments of nightmare, every day "Knights" fight against danger. Aoi Shirano, a normal boy, is saved by one of them, a girl named Yukino Tokitsuki. This meeting will change their lives forever.