Demons live amongst us. Their tendrils can be felt everywhere; they push at the edges of the minds of the vulnerable. Let us in, they whisper, let us in. And sometimes, sometimes, we say Yes. A handful of men and women stand between the world and this ultimate darkness, holding it back however they can. They are Exorcists, imbued with the authority to thrust demons out from the flesh they have made their home and hurl them back into the abyss. But the Exorcists themselves are only human and their adversaries are creatures of unfathomable power and malevolence – every human weakness is an avenue through which a soul might be lost. How long can they be kept at bay? How long can the darkness be held back?