1035, Amiens, France, 10-year-old Raoul and his cousin, Walter, make an extraordinary discovery—a talking Viking skull in the marsh of the Somme River. The skull introduces itself as Cnute Fine-Feather, a former Viking seer. Cnute asks for help to free his spirit from his skull. He explains that to release his spirit, Raoul and Walter must help defeat his kin, Viking draugrs (undead) who are trapped in Niflheim (Viking world of ice and fog) by day and Midgard (earth) by night. However, breaking the draugr curse requires the blood of a French noble. Despite being of noble birth and the danger to them and their families, Raoul and Walter accept Cnute's challenge. Joined by their friend, Gunhilda and guided by seeress, Loulou, the children learn the Viking art of seidr (story telling) and Web of Wryd and uncover connections binding them to Cnute and the Viking draugrs.