Dark days threaten Britain as invaders approach from the north and the Roman legions, former conquerors and present defenders, withdraw to the east. Meanwhile, Aedan ap Taran, a Briton in the service of the Emperor, finds himself pursued for crimes he did not commit. Forced to flee Rome, Aedan finds himself embroiled in a conflict of war and plotting in Britain, torn between his loyalty to the empire and to his people. Chaos threatens to plunge the Island of the Mighty into an era of darkness and superstition, and from the shadows will step forth a Winter King to either save or destroy the land.