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.

In the year 1002, the war between England and Denmark was intensifying. One day, the Jomsvikings pay a visit to Thorfinn's village in order to bring back Thors, their former commander, to prepare for the impending battle. Thors is forced to join the war in order to protect the villagers from being taken hostage, and must face his accursed past in order to save his family and his village.

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...

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's army separates from the army of Denmark and attacks a village 100 km to the west. Thorfinn leaves the soldiers behind in disgust and climbs up a hill overlooking the village, where he pledges revenge for his father. However, he encounters Askeladd sitting in the darkness, who tells him about "Britannia", the aging of the world, and Ragnarok, the final battle.

Thorfinn and Thorkell agree to have a duel over the fate of Askeladd. Thorkell looks forward to facing off against Thors’s son, Thorfinn, and asks him what a true warrior really is. Meanwhile, Canute is suddenly ambushed while he attempts to escape, and has a dream about a certain individual.

Thorfinn suffers a serious injury in his fight against Thorkell. Thorfinn is told to think about what he has to do to beat Thorkell. Askeladd treats Thorfinn’s wounds so that he may fight again someday, and proposes a joint strategy to help the two of them survive longer.

Thorfinn suffers a serious injury in his fight against Thorkell. Thorfinn is told to think about what he has to do to beat Thorkell. Askeladd treats Thorfinn’s wounds so that he may fight again someday, and proposes a joint strategy to help the two of them survive longer.

Canute’s party arrives in York to attend the Imperial Council. Although Canute had wanted to strike out against King Sweyn, the King was being guarded by the most powerful Jomsviking unit in the Northern Sea while keeping a close eye on Canute. With the situation strained to the breaking point, Askeladd comes up with a plan. Meanwhile, Thorfinn is reunited with a person who knew his former self.

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

Einar and Thorfinn are told to convert a wild forest into a wheat field; and if they succeed, they will have the chance to buy their own freedom.

Olmar feels insulted by Canute's messenger and, encouraged by his older brother Thorgil, takes matters into his own hands.

Einar says that even if he gains his freedom, he wants to stay near Arnheid. Snake hears news of a slave who killed his owners, and is now on the run.

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.

Arnheid comes to the fortress where Gardar is imprisoned. She wants to see her husband and treat his injuries.

As Snake intensifies his search, Arnheid tells Einar and Thorfinn everything she's done. Knowing the risks, Einar and Thorfinn offer to help her.

Snake strikes quickly, surprising Thorfinn with his speed and agility. As he lies wounded, Gardar thinks back on the life he shared with Arnheid.

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