Game of Thrones' strongest and most consistent narrative trick is its willingness to lie to us. In season 1, Game of Thrones didn't just kill off protagonist Ned Stark; the show took time to set up an alternate, entirely plausible story about Ned joining Jon Snow at the Wall before it suddenly chopped his head off. In season 3, we heard Robb Stark making extensive plans for his army, his wife, and his unborn son before he was suddenly murdered at the Red Wedding. Last night, the series pulled the same trick in the titular battle between the Mountain and the Viper. Oberyn Martell entered the arena, twirling his spear and vowing, "Today's not the day I die." His cause was just, his plan was sound, and he sounded so confident. How could he be wrong?

Less than 10 minutes later, Gregor Clegane was on top of Oberyn, crushing his head like an overripe pumpkin. The message is clear: You can say "not today" to the god of death, but it doesn't mean he'll listen. To paraphrase Tyrion's conversation with Jaime in "The Mountain and the Viper": As beetles to Orson Lannister are the people of Westeros to the gods. They kill them for our sport.

Yes, sadly, "The Mountain and the Viper" marks the end of Pedro Pascal's arc as the deadly, hedonistic Red Viper of Dorne. (It also, presumably, marks the end of Gregor Clegane — but given that Hafthor Julius Bjornsson is the third actor to play the character in four years, that loss is a little less painful.) Game of Thrones' one-season wonder characters haven't always made a strong impression — can you remember a single interesting thing Mance Rayder did? — but when I look back on Game of Thrones' fourth season, Oberyn Martell will loom very, very large in my mind. Give him a toast the next time you're enjoying a glass of Dornish wine.

But before "The Mountain and the Viper" reaches its title bout, it spends a lot of time moving pieces into place for the final two episodes of the season. The wildlings are still raiding their way across the north, though Ygritte spares the life of both Gilly and her son. Ramsay Snow uses Theon/Reek as the key instrument in the sacking of Moat Cailin, and is officially legitimized as Ramsay Bolton once he succeeds. (For his own success, Theon is given the honor of bathing Ramsay.) Grey Worm is beginning to have feelings for Missandei, though it's not likely he'll be able to do all that much about it. And Daenerys finally discovers that Jorah Mormont was spying on her in the early stages of her marriage to Khal Drogo and banishes him from Mereen as a sad (but relatively merciful) punishment.

Outside of King's Landing, the most interesting scenes in the episode belong to the Stark sisters. This is the closest Sansa and Arya have been since Arya fled King's Landing, and the closest Sansa has been to anyone in her family since she watched her father's execution. Arya and Sansa didn't exactly get along in the first season, but would they even recognize each other now? Arya has gone from spirited tomboy to cynical killing machine — the kind of person who lets out a blackly comic laugh when she learns her aunt died. And Sansa has learned well from Littlefinger, telling a modified version of Lysa's death that protects her protector — who is, given Littlefinger's disturbingly potent infatuation with her, the man she can manipulate most easily of all.

But as interesting as all these developments are, the meat of the episode comes down to the battle between the Mountain and the Viper. On a narrative level, this scene is a challenge; while Tyrion's fate hangs in the balance, this is really about a conflict between Oberyn, a character we just met, and Gregor Clegane, a character we barely know. To make things even less TV friendly, their conflict is centered on the death of Elia Martell — a character whom we never met, and whose rape and murder was committed years before the TV show even began.

It's a tall order — but at this point, there are few conventional narrative rules that Game of Thrones hasn't broken with aplomb, and it's no surprise that they pull this one off too. On a pure, physical level, this is the most thrilling battle Game of Thrones has ever staged, and Oberyn's bitter battle cry — "You raped her. You murdered her. You killed her children" — will surely rank among season 4's most memorable quotes.

He had to lose his life for it — but Oberyn does, in fact, get both his revenge and his confession from the Mountain. Tywin Lannister rarely gets his own hands dirty, but he's more than happy to align himself with men like Roose Bolton, Walder Frey, or Gregor Clegane when it suits his purposes. But while Tywin is powerful enough to stop a prayer at the beginning of a battle that will allegedly be decided by the gods, he can't drown out the voice of Oberyn, reminding Westeros' most powerful people of the bloody legacy their kingdom is built on. "Who gave you the order?" Oberyn cries, pointing to Tywin, and while Tywin doesn't respond — you can't draw blood from a stone — his silence speaks volumes.

Will the laws of gods and men ever hold him accountable? That depends on how you read Tyrion's story about Orson Lannister's obsession with killing beetles. "Nothing made him happier," says Tyrion as he recalls the rhythmic sound of his cousin smashing the beetles with a rock. "His face was like the page of a book written in a language I didn't understand, but he wasn't mindless. He had his reasons."

What were those reasons? Tyrion never figured it out, but you can get a glimpse of that same kind of glee on the face of a similarly inscrutable man: Tywin Lannister, who sentences Tyrion to death at the episode's end. Tywin may be a powerful and brilliant man, but he's not so different from the simple Orson, using all the power of Casterly Rock to crush anyone he chooses. "Far too much has been written about great men, and not nearly enough about morons," complains Tyrion to Jaime. And yet, Tywin and Orson's methods are disturbingly similar.

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