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.

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.

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.

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.

Thorkell takes Canute hostage and follows after the main army of Denmark. Ragnar objects to Thorkell’s plan to take on the entire army of Denmark, boasting 16,000 soldiers, with only 500 men. Thorkell then begins to tell Ragnar the story of Valhalla, the pride of Normans, a place where only those who die in battle can go.

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.

Einar i Thorfinn dostają zadanie przekształcenia dzikiego lasu w pole pszenicy. Jeśli im się uda, będą mogli kupić sobie wolność.