In the series, the ancient Norse prophecy of Ragnarök brings about a moonlit cataclysm in which most of humanity become werewolves. The plot charts the life of one of the few surviving humans, a dog pound worker called Rowan Morrigan who becomes a deadly werewolf hunter. The series is a trilogy. The second and third entries shift the story forward years at a time. In the final part, 35 years have passed since the beginning and Rowan is a mother in her mid-fifties.