Vikings Season 4
Vikings will have 20 episodes for season 4History Channel

The premiere episode of Vikings season 4 opened to great viewership numbers for History Channel. Titled A Good Treason, the first episode was completely about the lead characters and their betrayals. King Ragnar Lothbrok is sick and all his close people are betraying him one by one, including his brother Rollo. Show writer/creator Michael Hirst has hinted that there will be more problems between the warrior bothers.

"As far as the brothers are concerned, Rollo has confessed to what he thought was a dead Ragnar that he's never got over his jealousy. So Ragnar knows," Hirst told EW.

In the premiere episode, Ragnar was too sick to take any decision and his eldest son Bjorn took the chance to allow his uncle to stay in the city of Paris and pursue his dreams. It will be interesting to see how the King of Denmark will save his crown, which is being threatened by his enemies.

"And remember, it wasn't Ragnar who let Rollo stay. He was too sick to make that decision. It was Bjorn. Ragnar, I don't think, would have ever allowed Rollo to stay. And I don't think that Ragnar ever forgave Rollo. He just let him go because he was blood. I really don't think that Ragnar felt able to forgive Rollo," Hirst added.

In the premiere episode, Rollo not only married Princess Gisla to prove his loyalty to Paris and Emperor Charles but also slaughtered the remaining vikings in the city by taking them to a forest. During the ordeal, one soldier cried out that their king Ragnar would come to avenge their deaths.

However, the Norse King has his own issues to deal with, apart from thinking about his brother gone rouge. His son had captured and chained Floki who murdered Athelstan in season 3. Once Ragnar gained his senses, he realised that it was too late for him to save his old friend. "If I wanted Floki arrested, I would have done it a long time ago," the sick king told his son.

Bjorn, on the other hand, is still struggling to make his own identity among his famous parents (Ragnar and his former wife Lagertha). "He needs to prove to his father and mother — but more than that, to himself — that he can survive; he can grow up; he can be independent. Obviously he's going to go into the wilderness where he will face three very, very difficult and different kinds of trials. And I think he does return a changed man — it absolutely does change his sense of himself and his presence," Hirst told The Variety.

Vikings season 4 airs every Thursday on History Channel.