From bestselling author and screenwriter Mike Carey (Unwritten, Lucifer, Girl with All the Gifts) and Arvind Ethan David (Dirk Gently's Holistic Detective Agency) comes an all-new, original world of darkness and demons. When the demons came, humanity reluctantly learned to share the world with another sentient race. Eighty years later, this uneasy co-existence has spawned an endless terrorist conflict. Detective Daniel Aston, charged with being the thin blue line between the two sides, is tested to the limit when a demon sets up house inside his soul. But to save his daughter, he'll pay any price - including genocide.