After confronting a killer and fleeing her home to be with each other, Cat and Simon arrive in the sprawling city of Londunium pretending to be a newly married couple, but don’t expect to keep up the ruse for long. Cat looks forward to honing her healing magick at the local Selenae university, but instead finds a council of ruthless leaders threatening to erase her non-Selenae "husband’s" memories to protect their secrets. Terrified to lose him, Cat takes desperate steps to keep him safe. But when a string of mutilated bodies turns up in the woods outside the city, and Simon is recruited to profile the killer, Cat is pulled back into a world of murder, mayhem, and magick—one that threatens to swallow her, and everything she loves, whole.