Bjorn is reunited with his brothers Ivar and Hvitserk for a strange gathering after Bjorn is gravely injured in battle. As they share tales of the exploits of their people, and prophecies of Ragnarok, it becomes clear that this is not a simple reunion.

The epic saga which began with Ragnar Lothbrok, the first Viking hero to emerge from the mists of myth and legend, comes to an end in a spectacular and shocking series finale which finds tragedy striking in the new land and in England.

In the new land, Ubbe and the settlers engage in careful diplomacy when they are surrounded by the locals. In Wessex, the Vikings ambush the Saxon army, but Alfred is convinced the Lord is with his army and refuses to retreat.

Ubbe and the settlers find land, but soon realize they're not alone. In Wessex, King Alfred has mustered a large force to meet the Vikings. Meanwhile, in Kattegat, Erik realizes that Ingrid has been using her powers against him.

When King Alfred of Wessex hears about the arrival of the sons of Ragnar, with an army, he knows he must take drastic action. So as the Viking army makes camp and lies in wait, Alfred and his army abandon the Royal Villa and march to meet them.

Out in the open sea, Ubbe and the settlers are at the mercy of the elements. Tension mounts between Ubbe and Othere and when baby Ragnar begins to weaken, it's the final straw for Ubbe. Meanwhile, Ivar and Hvitserk return to Kattegat.

A fight erupts in Greenland and Ubbe, Torvi and Othere barely escape with their lives...in a leaking boat with no supplies. And in Kattegat, Gunnhild makes a bold move.

Prince Igor receives a hero's welcome in Novgorod but back in Kiev the mood is darker: Prince Oleg will not be giving up the fight. Meanwhile, Ubbe's settlers are overjoyed to find land, but it's not the Golden Land they expected.

It's Election Day in Kattegat and all eyes are on the voting. But strangers arriving at the harbor may force an unexpected outcome. Meanwhile, Ivar receives the signal from Prince Dir that his forces are ready to challenge Oleg.

The mood has changed when the Rus army returns to Kiev and Oleg isolates Ivar. But Dir confirms that he's mustering a force to overthrow Oleg and Ivar is part of the plan. Ubbe and a group of settlers depart Iceland, in search of the Golden Land.

In Iceland, Ubbe learns the truth about Kjetill and has a difficult decision to make. Back in Norway, the battle against the Rus has had grave consequences. But re-enforcements have arrived, and Bjorn has an idea that may yet save the day.

Ivar and Igor may be plotting against Oleg, but they're still part of the force that departs Kiev to invade Scandinavia. King Harald and King Bjorn begin furious preparations for the invasion. But can enough be done to resist the Rus force?

In Iceland, Ubbe and Torvi finally meet a mysterious wanderer. Bjorn is forced to re-think who his enemies are when Erik returns from a scouting mission with worrying information. Bjorn will need allies, but can he convince his old foe, King Harald, to join forces in the face of the new threat? Ivar is reunited with someone close to him.

Bjorn is confronted by a difficult choice to make; Ubbe and Torvi embark on a search for old friends and new lands after they leave Kattegat; Oleg's preparations for invading Scandinavia go as planned while King Harald investigates the raiding party.

Bjorn comes back to Kattegat; Harald manages to acquire a semblance of revenge against Olaf; Ivar and Igor learn information about Prince Dir while in Kiev.

Bjorn is forced to act quickly in the aftermath of the election for the King of all Norway. The bandits attack Lagertha's village again, confident of victory. But when the defense boils down to single combat with Lagertha, victory for the bandits looks less certain. Back in Kattegat, haunted and paranoid, Hvitserk continues to unravel.

King Olaf feels confident about the result of the election of the King of all Norway as the kings and jarls visit Harald's territory; Lagertha's village is abuzz due to bandit attacks; Ivar is forced to confront an unfortunate element of his past.

Lagertha leads her village's response to the recent attacks but despite her best efforts, when the inevitable attack comes, the consequences are tragic. Olaf has a bold new plan for the future of Norway. In Kiev, although Ivar discusses Oleg's ambitions for Scandinavia, he's actually more interested in the plight of Igor, the young heir who Oleg controls.

Lagertha is visited by women from the nearby villages and they feast together happily but the community is shattered by shocking events that follows and Lagertha is forced to take action. In Kiev, although Oleg continues to be friendly, Ivar is aware of the threat which Oleg poses, not only to himself, but to the vulnerable young heir to the throne. Bjorn has answered the call and come to the aid of an old enemy, but all is not as it seems and disaster looms for Bjorn's forces.

Messengers arrive in Kattegat with news that presents Bjorn with a dilemma. As Bjorn attempts to do the right thing as ruler of Kattegat, Prince Oleg of Kiev seems untroubled by his conscience. Even Ivar is shocked by Oleg's vicious character as he wrestles for control over the young heir to the throne of the Rus Empire. Lagertha has settled into her new, peaceful life, but danger lurks nearby.

It's six months after the battle of Kattegat and Bjorn is now King. But as he struggles with the responsibilities of kingship, he finds he can't rely on his mother, Lagertha--she has other plans. But can Lagertha lead a quieter life and leave her days as a shield-maiden behind? Ivar falls into the hands of the Kievan Rus, and in their ruthless and unpredictable ruler, Prince Oleg, he may finally have met his match. Intrigued by Ivar's claims to be a god, Oleg decides to put him to the test.

Ivar the Boneless has left Kattegat, on a journey to parts unknown. He encounters a stranger and is flooded with memories of his past, prompting Ivar to recount the saga of the enigmatic genius Floki.