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.

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.

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 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.

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.