Vikings - Season 4

Entry to Valhalla eludes Ragnar but as he lies in his sick bed in Kattegat events unfold beyond his control. Bjorn orders the arrest of Floki for Athelstan's murder and in Paris, Rollo betrays his allies to strengthen his position. Meanwhile, in Hedeby, Kalf announces joint Earldom with Lagertha, but is Lagertha actually willing to share what once was hers?

Floki hopes to escape from Ragnar and Kattegat. Rollo makes great efforts in Paris to win over his new bride, Princess Gisla. King Ecbert orders his son Aethelwulf to rescue Queen Kwenthrith from opposing forces in Mercia.

Floki faces the wrath of Ragnar. Intrigue prevails in the French Court as Rollo finds an unlikely ally. Kalf and Erlendur plot their ascent. Bjorn must fight a fierce opponent in the wilderness.

The Yule Log burns in the Great Hall in Kattegat and mysterious visitors are welcomed, among them a Norwegian King. King Aelle visits Wessex for Christmas and is concerned with how family relations are developing. In Paris, Rollo's future hangs in the balance - can he win over his new bride, Gisla, as a Papal Delegation arrives to arrange a divorce?

There's an air of betrayal at Court in Paris and in Wessex. Ecbert agrees to support Kwenthrith in Mercia, but is Ecbert a true ally? Ragnar confides in Yidu his darkest secret. Happiness comes to Lagertha and Kalf and a marriage is arranged.

Ragnar announces a raid on Paris at the Thing in Kattegat. The fleet is battered by a storm after it sets sail, but the greatest challenge for the Vikings lies ahead in Paris, where Rollo awaits. Meanwhile, Ecbert dispatches Aethelwulf and Alfred on a pilgrimage to Rome.

On the Seine, the Vikings attack with considerable force but can they breach Rollo's defenses? Meanwhile, Harbard, the mysterious wanderer, returns and causes a stir amongst the women of Kattegat.

The Vikings call Ragnar's leadership into question. Ragnar himself remains inscrutable and orders the fleet to beach at a cliff face where he unveils an ingenious plan. Rollo and Gisla have news that strengthens Rollo's position at the French Court.

The labours of the Vikings bear fruit as, within sight of Paris, they re-launch their fleet but this time with some formidable new structures that Floki has engineered. Aethelwulf and Alfred arrive in Rome and honours are conferred by Pope Leo. Relations are not so cordial in Wessex.

A fierce battle between the Vikings and the French eventually comes down to Ragnar against Rollo and the outcome seals the fates of the two brothers.

Ragnar has returned to Kattegat and there are secrets to be revealed. He makes plans to return to Wessex to right past wrongs but finds that those who were once his closest allies now have plans of their own. Even the Lothbrok sons refuse to join their father's mission – except one.

The Kattegat locals chide Ragnar that the gods have deserted him as he struggles to crew his voyage to Wessex. It's Bjorn who has charisma now as he prepares to fulfill his long-held dream to explore the Mediterranean in a sleek new boat built for him by Floki. By contrast, Ragnar must accept weathered boats and a crew he has bribed but when Aslaug foresees that the fleet will be lost in a vicious storm her warnings go un-heeded by Ragnar and her precious son, Ivar.

Ragnar's fleet is shipwrecked and washes up on the Wessex coast, but without enough survivors to form a credible force, Ragnar and Ivar have a difficult decision to make. Rollo meets his Viking comrades again and can't resist the urge to join Bjorn's voyage, risking his marriage and his new Frankish identity. Ragnar too is taking a risk as he carries Ivar towards the Royal Villa in Wessex – throwing himself and his son upon the mercy of King Ecbert.

Lagertha attempts to fulfill a long-held ambition. Ragnar negotiates an unexpected concession from King Ecbert.

Ragnar and Ivar plot against the Saxons and reach a new level of understanding.

Bjorn's fleet sails onward and launches a surprise attack; back in Kattegat, Lagertha continues in her quest for power.

The Viking army begins to gather in Kattegat; Lagertha must remain vigilant in the absence of her son, Bjorn.

Ragnar's plan comes to fruition; the Viking army lands on the coast of Northumbria.

The Viking army causes panic in the English countryside as King Ecbert and Aethelwulf plan the defense of the realm.

Prince Aethelwulf finds himself subject to the Vikings' battle master plan; Ecbert remains behind with a plan of his own.