War has come to Britain. The High King Ambrose is too old and infirmed to continue his duties, leaving men to wonder who will succeed him. Will it be the Christian, Gorlois, Duke of Cornewall, or will it be the relentless tyrant, Lot of the Orkneys? There is a third choice in the Welshman, Uther, a follower of the Old Religion with the power of the Druids behind him, but it seems civil war cannot be avoided. As the Britons prepare for the inevitable, an ancient darkness creeps into the land and threatens to exterminate the Druids once and for all. The future of the Old Religion and Britain itself rests in the hands of a True King, prophesied to rise and become the Pendragon, and a young man named Galahad, Prince of Lodecran and apprentice of the great Taliesin. Galahad is called to the Unseen Vale to take up the robes of a Druid, destined to one day become the Last Merlin, but only if he can survive the greatest trials Britain has ever known...