A serial killer is loose in Yorkshire, claiming three lives in as many months; always following the same chilling pattern. Eleven days before each murder, a large purple V is painted on the victim's front door. The victims are found drained of blood with two red marks on their neck, and all are murdered beneath a full moon. When Ruby Barnett comes home one evening to find her front door market, it's clear she is the so-called Vampire Killer's next victim. Private Investigators Kitt Hartley and Grace Edwards have just eleven days to solve the mystery and save Ruby's life. Can they catch the killer before it's too late?