Thorfinn, a boy living in Iceland, longs for adventure and is eager to know more about the world. He dreams of a land of paradise called Vinland that he hears about from the adventurer Leif, while he leads his peaceful life with this father Thors, a former warrior. One day, Thors saves a runaway slave and sets a series of events in motion. This is the story of a true warrior in an age of turmoil.

Askeladd, the leader of a Viking army of a hundred men, receives orders from Floki of the Jomsvikings to kill Thors, who was once known as the Troll of Jom. However, the villagers, completely unaware of the order, buzz with excitement as they prepare for their first battle. Thorfinn also joins in the excitement. Thors and his men are about to embark on a difficult sea journey to England.

Thors and his men fall for Askeladd's trap and faces a dangerous situation, but Thors defeats many of Askeladd's men with his overpowering strength. However, Thors knows that it will be difficult to save everyone, including his son, who've been living in a peaceful village their entire lives, and makes a tough decision.

After Askeladd kills Thorfinn's father Thors, Thorfinn hides inside Thor's ship and bides his time until the opportunity to take revenge. However, life on the ship is harsh without any food or water, and Thorfinn grows weaker day by day. One day, Thorfinn, armed with his sword, attempt to attack Askeladd in his sleep...

Thorfinn kills his first man. As more time goes on Thorfinn kills more men and becomes more skilled. One day when Thorfinn is in battle he gets shot with an arrow and ends up unconscious. An English woman and her daughter help him recover.

After capturing the treasure from the Franks, Askeladd's men return to the village of Gorm on the Jutland Peninsula in Denmark to pass the winter. Thorfinn challenges Askeladd to a duel as a reward for bringing him the head of the captain of the clan of Franks. Even though Thorfinn has grown in skill through his experience in battle, he is still no match for Askeladd.

In October 1013, King Sweyn leads a fleet of Danish and Viking ships in an attempt to take London Bridge of England. Askeladd's army, hired by the army of Denmark, was among them. However, after the betrayal of Thorkell the Tall, a Viking known for his overpowering strength, London Bridge has become impregnable. Askeladd tells Thorfinn he'll reward him with a duel if he's able to kill Thorkell.

Askeladd crosses the river and escapes from Thorkell into Wales with Canute. However, Askeladd’s men are ambushed by a group of soldiers hiding behind the boulders at the border of the kingdom of Brycheiniog. Askeladd attempts to negotiate with their messenger and reveals his plan.

After losing Canute, Thorkell decides to halt his advance in central England. Thorkell hears that the end of the war between Denmark and England is near, and bemoans the end of the war. However, he later gets wind of an interesting piece of news.

Askeladd and his men are attacked by the English army in the village where they had planned to camp during the winter. Askeladd captures their captain and interrogates him to find out how the English knew where they were, and discovers that Thorkell is fast approaching. The news of Thorkell's arrival sends waves of shock among Askeladd's followers.

Einar lives peacefully in northern England with his mother and sister, but then one day, their village comes under attack.

After everything that happened, Einar asks Thorfinn if he's ever fought in a war — and if he's ever killed a man.

Thorfinn has nightmares almost every night, but he can never remember what he dreamed about — and that bothers him.

A runaway slave appears on Ketil's farm, claiming to be Arnheid's husband. But before he can free her, he's confronted by Snake.

Amidst the confusion of a peasant uprising, Thorfinn and the others try to escape, carrying a severely injured and pregnant Arnheid.