After confronting a killer and fleeing to be with each other, Cat and Simon arrive in the sprawling city of Londunium. Cat is looking forward to honing her healing magick at the local Selanae university, but instead finds a council of ruthless leaders threatening to erase Simon's memories to protect their secrets.

Terrified, 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 consume her completely.