The year is 1069. The kingdom of England is in the grip of new Norman masters. Their castles rise up all over the countryside, dominating the landscape. The Viking menace from the north is just a distant memory. Or is it...? The disempowered Anglo-Saxon earls of the north have few friends to help them against their hated Norman overlords. But help is at hand from an unexpected quarter. King Sweyn of Denmark has followed in the footsteps of his Viking ancestors, landing in the Humber estuary and promising aid for Edgar Atheling, the teenage heir to the stolen crown of England. Sweyn, Edgar and their allies advance on York, determined to destroy the Norman castle and to wrest control of the city from William the Conqueror. The reconquest of York will open the way for the northern earls to battle their way south and perhaps to oust William entirely. But will Sweyn be true to his word? After all, what is the promise of a Viking worth..?