The fourth season of "Vikings" has done a good job showing Ragnar's slow descent into madness. The once mighty Viking king has been hobbled with injuries, is addicted to Yidu's "medicine," and has just suffered a major defeat at the hands of his brother, Rollo. But can Ragnar still turn things around?

Fans could clearly see how Ragnar's (Travis Fimmel) dependence on Yidu's (Dianne Doan) medicine is affecting him. In one scene, Harald Fairhair (Peter Franzen) and his brother, Halfdan the Black (Jasper Paakkonen), approached Ragnar to commend him on his brilliant ploy to transport the ships over the mountain. While they were effusive in their praises, viewers can see Ragnar struggling to stay in the moment, as he seems so out of touch. He's later seen demanding more medicine from Yidu, and when she refused and threatened to expose the slaughter in Wessex, he ruthlessly drowned her and took her stash.

Viewers will soon see whether Ragnar's plan will work or not, as the Vikings draw nearer to Paris and the midseason finale. A synopsis for episode 9, "Death All 'Round," reveals that the Vikings will soon relaunch their boats, this time nearer to Paris. Interestingly, their boats will have new structures that have been built by Floki (Gustaf Skarsgard). Meanwhile, Aethelwulf (Moe Dunford) and Alfred (Conor O Hanlon) arrive in Rome and are greeted with honors by Pope Leo. However, relations between King Ecbert (Linus Roache) and King Aelle (Ivan Kaye) quickly turn sour.

Aside from Yidu's shocking death, episode 8 also saw Queen Kwenthrith (Amy Bailey) die at Judith's (Jennie Jacques) hands and Count Odo (Owen Roe) murdered by his mistress and Roland (Huw Parmenter). Now it seems that another death is on the way, if the trailer for the upcoming episode is anything to go by.

The trailer starts with Ecbert being crowned King of Mercia, but amid all the cheering, one man is clearly unhappy — King Aelle. Northumbria's ruler is later shown accusing Ecbert of betrayal, to which he replies that Aelle should get used to it. Back in France, the King is seen receiving Rollo (Clive Standen) and Gisla (Morgane Polanski), but he doesn't seem too happy. Gisla is then heard saying that the person closest to her father is the most powerful. That person appears to be the King's lover.

The clip also reveals that Ragnar's fleet is back on the water. The Viking king is later seen eyeing the French castle from his vantage point in a mountain, while running his hands over Yidu's medicine pouch. He later reveals that he doesn't care for Paris, that he came for his brother Rollo.

The clip ends with Torvi (Georgia Hirst) facing Bjorn (Alexander Ludwig) with a crossbow. Sporting a bloody lip, she tells Bjorn that Erlendur (Edvin Endre) ordered her to kill him as vengeance for his father's death. Bjorn calmly faces her and asks what she's waiting for.

It's unlikely that Bjorn will be killed at this point, but Torvi might do considerable damage with that weapon. However, it's more than likely that either Torvi or Erlendur will be killed in this scene.

Episode 9 of "Vikings" season 4 will be aired on the History Channel on Apr. 14.