Late ninth century, a small island in the North Atlantic. King Orvandill returns from a campaign with a serious injury to his wife Gudrun and young son Amleth. Dreaming of going to another battle and dying on the battlefield, he hands over the throne to his son, but is immediately killed by his brother Fjolnir, who cuts off the monarch's head and takes the kingdom and Gudrun for himself. The boy manages to escape.
Decades later, Amleth grows into a strong, ruthless Viking, and one day in another ruined village he meets a witch who sets him on the path of revenge. After learning that Fjolnir and Gudrun have settled in Iceland, Amleth travels there with a shipment of Slavic slaves. On board, his attention is drawn to Olga of Birchwood.