‘Vikings’ Season 4 Spoilers: Midseason Finale Synopsis Released; What Will Happen In Episode 10? [VIDEO]

Everything has been leading up to this moment — the moment when Ragnar faces off against his treacherous brother Rollo in an epic battle. And, according to the promotional video for the midseason finale of History Channel’s “Vikings,” the sibling rivalry won’t cease until one of them is dead.

“One of us will die today,” Ragnar (Travis Fimmel) warns his brother in a trailer for episode 10.

“And it won’t be me,” Rollo (Clive Standen) replies moments before the brothers clash swords.

The summary of the next installment, titled “The Last Ship,” reveals that the battle between the Northmen and the French will “prove to be costly.” This leaves fans wondering whether Ragnar or Rollo or both will wind up being casualties of war.

Each brother has his own reasons for wanting to see the other dead. Rollo has been itching to crawl out from Ragnar’s shadow, and he was finally able to see the light when Bjorn (Alexander Ludwig) left him behind in Paris after their victorious raid.

Rollo has since climbed the regal ladder in Paris, becoming the husband of Princess Gisla (Morgane Polanski) and the count of Frankia. But, despite his success in the city, Rollo has indicated by his actions he can never truly find peace until his famous brother is dead.

Meanwhile, Ragnar has had enough of Rollo’s betrayals, and now his brother must pay for his treachery. In episode 9 of “Vikings,” Ragnar reveals to Bjorn that he no longer desires to raid Paris. He only wants to put a blade through the heart of his brother. And to do that, the king of Norway is saving his last pill, given to him by Yidu (Dianne Doan), to provide the strength he needs to take down Rollo, once and for all.

Which brother do you think will be victorious? Sound off in the comments section below. “Vikings” will air its midseason finale on History Channel Thursday, April 21.