After taking the Memorial Day weekend off, Game of Thrones returns tonight with a brand new episode, "The Mountain and the Viper." There are several significant scenes slated to occur in this episode. If you haven't read the books and just can't wait to know what happens (who needs all that stress?), or would maybe like to know the outcome of Tyrion's trial-by-combat is, then you've come to the right place. This should be obvious, but SPOILERS follow. Littlefinger will have his authority challenged. The previous episode, "Mockingbird," ended with a real shocker. Petyr Baelish kicked his new wife, Lysa Arryn, out of the Eyrie's Moon Door and she fell thousands of feet to her death on the mountains below. Obviously, members of the Westeros' great houses can't just fall out of windows without someone noticing. Littlefinger will declare himself Lord Protector of the Vale and take young Robyn as his ward, but his claims won't go unchallenged. The highest lords in the Vale suspect that Petyr may have been up to no good all along. In the books, Petyr places blame for Lysa's death on a minstrel who played in the Eyrie, but that minstrel was never introduced in Game of Thrones. Whoever gets blamed, Littlefinger's authority will still be challenged. A lord on Petyr's payroll will act in a way that provides Petyr with a trial period as Lord Protector, a period he intends to use to tighten his grip on the Vale. Jorah Mormont's secret will be revealed. I had thought this would have happened earlier in the season, since it happens earlier in the books, but the recap that airs before tonight's episode basically guarantees it will happen tonight (Jorah goes away for a while after this in the books, and I'm guessing they delayed it so that they'd have something for Iain Glen to do for the rest of the season). If you remember, way back in season one, a meeting of the Small Council revealed that Varys was receiving correspondence about Daenerys from Jorah Mormont. Daenerys is going to find this out for the first time in tonight's episode. In the books, Jorah is too proud to admit that he had ever done anything wrong and so Dany can't forgive him. I don't know if that's exactly how they'll play it on Game of Thrones, but expect Jorah to be banished from Dany's ranks. Mole's town receives visitors. The official description for "The Mountain and the Viper" suggests that someone is going to be showing up unexpectedly at Mole's Town. In the book's, this is just Jon Snow riding up to warn them of the impending attacks by the Wildlings. This still may come to pass in the show, but the pre-episode recap makes a point of showing the brutal Wildling raids that have already taken place. Between this and the fact that Ginny has conveniently been placed in harms' way, thus heightening the drama, I wouldn't be surprised if the Wildlings actually get there before the Night's Watch can warn them, setting up a nice warm up battle before the big siege of the wall in next week's episode. Oberyn Martell loses. A now for this evening's main event! We know that the duel to decide Tyrion Lannister's fate will occur during this episode. That is, after all, where the episode gets its name. And the result? Oberyn will lose. In fact, in the books, Oberyn gets his face beaten in so badly that Tyrion vomits at the sight. I know, I know, you're upset. So was I. Oberyn Martell is an awesome character and Pedro Pascal has done a fantastic job portraying him, but he's just not meant to be around for very long. If it's any consolation… The Mountain also dies. ...eventually. I'm not sure if this will occur entirely in this episode, or maybe just be hinted at, but the key event definitely happens. The Red Viper got his nickname because of mastery of poisons. He coats his blades in poison before he fights the Mountain, so even though the Mountain wins and walks away from this battle, Oberyn still knows that he has sealed Gregor Clegane's fate. Maybe…there's even more going on with the Mountains death than that…but that's a spoiler for another episode. Game of Thrones, "The Mountain and the Viper," airs Sunday, June 1 at 9 PM ET on HBO.