On a chilly morning in February, DCI Claire Pierce is called off her latest investigation--an animal sacrifice case--to a graveyard in Nottinghamshire, where a murder scene looks set to re-open an old case. Three times before, Yorkshire's Ritual Crime Unit tried and failed to catch the "Valentine Vampire," a ritualistic serial killer whose victims show up drained of blood. Fourteen years after the last deaths, it seemed the case would never...