By the autumn of 537 AD, all who are loyal to King Arthur have retreated to a small parcel of land in north Wales. They are surrounded on all sides, heavily outnumbered, and facing near certain defeat. But Myrddin and Nell, two of the king's companions, have a secret that neither has ever been able to face: each has seen that on a cold and snowy day in December, Saxon soldiers sent by Modred will ambush and kill King Arthur. And together, they must...