'Game of Thrones': 7 Clues About 'The Mountain and the Viper'

Oberyn has his work cut out for him as he is set to face off against the bigger, meaner Clegane brother.

Game of Thrones is poised to unleash the Viper.

Oberyn will finally get his chance to exact revenge against The Mountain when the two compete in Tyrion's trial by combat. Judging by the preview (above), there are a lot of moving parts in the episode, but the climax will almost certainly be the big duel. Director Alex Graves told The Hollywood Reporter earlier this season that the upcoming episode, "The Mountain and the Viper," is the show's biggest ever (or at least tied with the season-four finale). That's saying a lot, considering Graves also directed this year's Purple Wedding episode.

Here we break down our theories on what's to come.

1. Theon is back

Yep, poor Reek is getting to use his real name again — but only as a pawn in Ramsay's sick games.

2. Theon will attack Moat Cailin

We've known for a while that Ramsay has wanted Theon to bring him a castle, and his father, Roose, commanded him to take Moat Cailin several episodes back. The area historically has been a key point for defending the North, and currently is occupied by Theon's father's men, so using Theon against his own people is particularly cruel.

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3. Sansa may sell out Baelish

Lysa's disappearance through the Moon Door was bound to raise questions. Sansa is shown addressing a roomful of people, with Littlefinger looking on. "Lord Baelish has told many lies. I have to tell the truth." The question: Will she actually tell the truth?

4. Mance's men raid Mole's Town

Not long after Sam shipped his lady friend Gilly to Mole's Town, it gets sacked. The trailer shows Sam tearing up, which doesn't bode well for Gilly. Jon has other worries, noting that Mance's men can't be far: "If they hit Mole's Town, then we're next."

5. Oberyn gets a good-luck kiss before battle

The Red Viper will finally get his shot at revenge, though his lover Ellaria Sand is worried about his chances against The Mountain: "You're going to fight that?"

6. The Mountain has a huge sword

Maybe Bronn was smart not to tangle with this guy.

7. But Oberyn has an even bigger spear.

Game of Thrones returns June 1.

Email: Aaron.Couch@THR.com
Twitter: @AaronCouch