Arcane archivist Harper has always been plagued by dreams of grotesque creatures and bloody deaths. When she bumps into a ghostwalker in the Shambles and has a visceral experience of his execution, she knows it's a foretelling. Yet fear of the Queen's Guard stops her speaking out. When her vision indeed comes true, the unusual markings on the ghostwalker's corpse, combined with his neatly excised vocal cords, send a ripple of terror through York.

The witch hunt is on. As the body count rises, Harper knows her magic is the only way to find the killer - if she can avoid being hanged as a witch. To protect both human and supernatural, Harper walks the thin line between their worlds. She and her demonhunter foster-sister form a multi-faith team with a forensic scientist, a spirit Harper accidentally summoned, and a techno-witch, to catch the killer before more people die.