The story takes place in England shortly after the Norman Conquest. High up among the mountains of the Lake District is a secret valley where the Northmen (Vikings) have their last stronghold - or shield ring. The Normans want to crush this last group of Northmen and bring the whole country under their control. To this end they build a castle in Carlisle and send an army north. Life goes on in the valley: lambing, shearing, spinning, harvesting, and singing and storytelling in the great hall in the evenings - as narrated by two young people.
Frytha is a Saxon girl, who fled to the valley after the Normans burnt her home, and Bjorn, the Bear-Cub, is the foster son of the old harper. As the people of the shield ring go about their lives, they stay ready for a Norman attack. Bjorn's foster father teaches him to play the Sweet-singer, a special harp that the old harper owns, and despite Bjorn's enthusiasm, a secret fear burns inside the boy: if the Normans capture Bjorn, he may succumb to torture and reveal the path to the hidden valley.
When the Northmen need to scout the extent of the Norman army, Bjorn volunteers: he speaks enough Norman to get by and a harper can go anywhere. The young man sets out for the Norman camp, not knowing that Frytha, an ally, follows him. He does know that if the Normans discover his espionage, though, he will be tortured, and his secret fear from childhood may become a reality.
England