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...

Askeladd withdraws temporarily from the war against England. While searching for a new source of income, he encounters a skirmish among the Franks and hatches a plot to steal their treasure. Askeladd sends 16 years old Thorfinn, who has grown up into a cold-hearted Viking, ahead as a messenger.

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.

Askeladd and his men change course and decide to return to Gainsborough, by crossing through the Earldom of Mercia in the midst of a harsh snowstorm, where the main army of Denmark awaits. The men spot a small village in the blizzard and make their move.

Askeladd's men continued their march to escape Thorkell. However, Torgrim and his friends were hatching a plot to switch sides and join Thorkell, taking Canute with them. Torgrim finally launches his rebellion and corners Askeladd, negotiating with him to hand over Canute, then Thorkell arrives in the midst of the confusion.

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.

Thorfinn begins his duel against Askeladd with Canute and Thorkell as witnesses. However, Thorfinn is unable to strike as he stands overwhelmed by the extraordinary mood that overtakes Askeladd after Bjorn's departure. Having noticed Thorfinn's hesitation, Askeladd lays down his sword and provokes Thorfinn into an unarmed fight, which incites Thorfinn's fury.

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.

Thieves have been stealing food from Ketil's farm. Meanwhile, Ketil's eldest son Thorgil returns home.

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

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

At long last, Thorfinn returns to Iceland and finds a moment of happiness, reunited with his loved ones. But soon, he opens up about his next journey.