"Vikings" is back, and it does it in style, with a solid episode that puts the basis for some story lines that will probably be developed throughout the season.
Ragnar is in limbo, after getting hurt at the end of season 3; he may die, he may not, and his wife Aslaug is actually quite interested in the probabilities of a queen inheriting the throne. Bjorn puts Loki in "prison" for the death of Athelstan. Lagertha goes back with Kalf and both decide to rule together. And our friend Rollo tries to get used to the French lifestyle.
All in all, quite a lot of plot development happens in the episode, and quite of interesting moments (even though none are very surprising and it's pretty obvious a couple are put just to bring blood and violence to the screen).
Being in its fourth season, "Vikings" is in danger of falling into repetition. But for now, it is doing a good job of keeping the watcher engaged. And with amazing characters as Ragnar, it is actually easy to make it interesting and entertaining.