Twelve days to Christmas and in snowbound London, a prostitute is found with her throat cut. Six hundred miles away, on a remote Shetland Isle, the body of another young woman lies sprawled at the foot of an ancient tower. Scarcely has Detective Inspector Jack Dawes probed the first blood-soaked corpse when a sudden epidemic of swine flu in the Northern Constabulary sends him speeding north to investigate the second murder. Jack travels to Doomdochry, a gaunt monstrosity of a castle, set high above the waves of a savage Shetland coastline. For five centuries it has been held by the sinister MacAlister clan, who resent police intrusion. Dawes has his work cut out. Their reticence could imply involvement in murder or something much worse. Floundering on unfamiliar territory, Dawes confronts an intelligence equal to his own and a ruthless killer, set to strike again. Finally, a terrifying showdown provides the link he needs to solve the murders