Things are just getting more intense as the brand-new season 4 of History Channel's hit historical drama TV series "Vikings" moves on this week with an episode that could see someone's life getting endangered, while another one wins the loyalty of an unlikely person.

The teaser trailer from the network reveals just how complicated the upcoming episode will be. The clip opens up with a shot of King Horik's son, Erlendur, talking to an enormous Viking, instructing the latter to kill someone in any way he sees it fit. Fans may already know the target in question: Bjorn.

Ragnar's mighty son is currently on his trek into the icy wilderness where he will get to meet a 10-foot bear. But the sheer size and ferocity of the animal won't budge the steely determination of the prince to survive. The video briefly shows Bjorn's face sprayed with blood, signifying that he may have overcome his enemy. Will Erlendur's assassin suffer the same fate in Bjorn's hands?

Another not-so-surprising development is also featured in the video. This time around, it involves Rollo suffering the cruelty of his Frankish bride.

"You ignorant savage!" Princess Gisla said with an utter contempt at Rollo as she throws water into the Viking's face. The synopsis from Zap2it.com says that Rollo will find an "unlikely ally" in Count Odo. Perhaps this could be on the matter of the woman?

Another interesting piece of detail from the teaser also indicates that this episode could see the return of Harbard. Speculations pointed out that it could be Harbard who will plead Ragnar to spare the life of Floki.

Speaking of the latter, the boat maker and Ragnar's best friend can still be found in the episode suffering the consequences of his sins. However, there's an ominous hint that the punishment could go bloody when Ragnar is shown bringing his axe into the cave.

The video fades out and a quick sound of someone getting hacked can be heard.

Find out how these events unfold when "Vikings" season 4 episode 3 "Mercy" premieres this Thursday, Mar. 3 at 10 p.m. on History Channel.