The Vikings are ready to set sail for season 4.

'Vikings' Season 4 Release Date: How Far Will Gisla Go To Get Away From Rollo? Episode 4 Teasers

Ragnar, Rollo, Bjor, Lagertha, and the rest of History Channel's stellar cast will return for the season premiere tonight at 10 p.m. ET. For those without access to a television, "A Good Treason" can be live streamed online.

Picking up in the wake of Ragnar's successful raid on Paris, the opening episode will see the conquering heroes return to Kattegat. The King of Denmark is still under the weather, and Bjorn will have to step up in his stead. It remains to be seen who will be more displeased with this arrangement - Ragnar or Aslaug.

'Vikings' Season 4: Someone Is Plotting Against Bjorn, Scoop On 'Mercy'

"Entry to Valhalla eludes Ragnar but as he lies near death in Kattegat events unfold beyond his control. Bjorn orders the arrest of Floki for Athelstan's murder while in Paris, Rollo betrays the last of his Viking supporters to strengthen his position in the French Court," History teased. "Meanwhile, in Hedeby, Kalf announces joint Earldom with Lagertha, but is power-sharing Kalf's true intention and is Lagertha actually willing to share what once was hers?"

Catch a live stream of "A Good Treason" by clicking here.

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