A man possessed. A witch who is determined to save him. And a demon who will stop at nothing to claim them both. Ava Helacourt has never met a demon she couldn't exorcise. Outcast amongst the other witches in her coven and estranged from her own family, Ava only finds solace from her dark past in her studies as a demonologist to protect the mortal realm from the monsters that creep in through the rifts between the two worlds. When Rory, a man possessed by a demon who calls himself Vain, is captured by her coven, Ava throws herself headfirst into untangling the web surrounding the two of them. Even when Rory seems to have lost all his will to fight back against the demon who refuses to leave his human vessel, she is determined to free him from his lustful and tempting captor. But as the lines between human and demon begin to blur and it becomes clear that their connection is deeper than she initially realized, Ava starts to question everything she has ever known, and must decide how far she is willing to go in order to save Rory's soul. Even if that means ruining hers in the process.