The central plot mechanic that'll drive us to the end of this Game of Thrones season finally reveals itself: Jon needs to prove to ally and enemy alike that the White Walkers are both real and spectacular.

But, see, we the audience already know they're coming. We've seen them marching south ... slow as particularly creepy molasses ... for like five seasons now. But most of the show's characters haven't seen them, so at least the next two episodes will be spent getting everyone up to speed. ("OK, who just joined the call? Cersei, is it? Jon, maybe you can go back a few slides in the deck to make sure Cersei's on board.") That's a recipe for audience frustration, unless the show can offer up some visual candy to keep us sated.

So it's likely no coincidence that next week's episode will be this season's second-to-last, historically when the show delivers its biggest payoff. Expect a huge battle (and some heartbreaking casualties) between Northmen and Evil Unstoppable Skeletons. Furs vs. Femurs, call it. The rumble-a in the tundra.

And I'm still predicting the Wall's gonna come a-tumbling down — there have been just way too many references to its eternal! Resolute! Steadfastness! for it not to — and there's no better time than next week's episode.

But, first, this week! We zoom over the map like we always do: King's Landing, Dragonstone, Winterfell, The Wall ... wait! Instead of swerving back down to Oldtown, we sort of ... scooch down the Wall a bit, to Eastwatch, the castle on its easternmost edge! Woo! New location! (Look, this episode's basically setting us up for next week, so we take our thrills where we can find them.)

Don't be Tarly for the parley

We open on a lovely, placid river scene you could imagine J.M.W. Turner painting, though instead of a quaintly bucolic name like "Neapolitan Fisher Girls Surprised Bathing by Moonlight," it'd have to be called something more like "Riverside With Black Plumes of Smoke Rising From a Few Hundred Charred Bodies Because There's A Friggin' Dragon For Real You Guys." Bronn pulls himself, and Jaime and Jaime's steel armor out of the river like he's gathering so many water lilies because Bronn gets tremendous strength when exposed to the rays of Westeros' yellow sun, I guess we have to tell ourselves.

Jaime is chastened by the extent of the carnage unleashed by only one of Dany's three dragons, and Bronn informs him that he doesn't plan to be around when she and her fire-breathing moppets attack Kings Landing.

Tyrion surveys the blasted battlefield, which looks like Mother Courage crossed with Pompeii. He's feeling guilty, seeing so many members of his House reduced to carbon. The few Lannister soldiers who made it through the battle are marched up a hill to stand before Dany and Drogon. The Mother of Dragons proceeds to put a Targaryen spin on her Sermon on the Mount that's less "Blessed are the meek" and more "Kneel or burn, jerkwads."

It's a good speech, but it convinces only a handful of soldiers. It's really Drogon — her hype man — whose roar sends most of the prisoners down on their knees. Except, of course, for Randyll Tarly, Sam's dour dad, and Dickon Tarly, Sam's poorly named but excellently cheekboned brother.

Tyrion pleads on their behalf, but Dany's all "They made their bed, now they have to fry in it," and with a puff from her magic dragon, Randyll's a candle, and Dickon is Dickoff.

OK, let's take stock. Sam is still around, but House Tarly is effectively snuffed out. Ditto House Tyrell, and House Martell. Plenty of lesser houses are in similar states of disarray. House Frey is finished, House Tully is bouillabaisse, House Party is over, House Music muted, House Boat is scuttled, House Plant died of thirst, House Elf is shelved, House Salad wilted, House Dressing scattered to the Thousand Islands, House Red is dead, House White is corked, House Speaker is very concerned, and House Hunters are really just awful people who think the universe owes them an open-plan kitchen.

As for the fates of House Baratheon and House Lannister, well, that's all about to get ... more complicated.

A singed Jaime storms into Cersei's chamber to deliver the bad news. "This isn't a war we can win," he says. He then informs her that Olenna Tyrell — and not Tyrion — ordered Joffrey's death. It's yet another instance of us watching characters play catch-up to stuff we already know, but it pays for itself here because Jaime lays out the steel-trap logic behind Olenna's plot, which is something I, at least, hadn't especially considered.

Jon ups his aunty

Dany returns to Dragonstone on Drogon's back, alighting near a spot where Jon stands brooding on a cliff, cape flapping dramatically behind him like he's Bat-Hamlet. Jon and Drogon share a nice moment, presumably because Targaryen game recognize Targaryen game, and Dany asks about Davos' "knife through the heart" comment. Jon plays it off, but the nice family outing is interrupted by the return of Jorah Mormont looking older, wiser and decidedly less like a frilled lizard.

Dany and Jorah hug, and Jorah shoots Jon a look that's nuanced, wary, appraising, resigned.

Jon shoots a look back at him that says, "It windy."

Back at Winterfell, ol' Cracklin' Oat Bran himself, the Three-Eyed Raven, wargs himself into an unkindness of your basic, garden variety two-eyed ravens (or maybe crows?), and flies north, over the wall, where he/they spot the army of the dead, shambling south with the terrifying speed of a tortoise on indica.

At the Citadel, Sam walks in on a meeting of maesters — The Beige Council — just as they're discussing a message from Bran, warning about the White Walkers. Sam urges them to take action, but they suspect it's a ploy by Dany to lure southern armies north, leaving Westeros' cities undefended, which would be a pretty solid plan, actually.

At Dragonstone, Tyrion attempts to rationalize Dany's ... draconian methods, but Varys is having none of it. In the map room, Jon reads a note informing him that 1. Arya's alive! 2. Bran's alive! 3. Bran's spooky now! 4. White Walkers are nearing Eastwatch.

Tyrion comes up with the plan: Capture an evil ice zombie and show it to Cersei to convince her that the threat is real. Meanwhile, smuggle Tyrion into Kings Landing to meet with Jaime to negotiate. This is a pretty complicated plan.

Sister Act 2: Back in the habit. Of disagreeing

At Winterfell, Arya seems bored without having even one lousy face to slice off and wear. She wanders into a meeting in which the various lords of the North grumble about Jon's absence and express their preference for Sansa. Sansa thanks them but politely demurs, which isn't enough for Arya, who'd prefer she'd instead react by lopping off some lord-melons.

Sansa attempts to explain to Arya that a gentle hand will get you further than an iron fist, but in Arya's mind she's just maneuvering to become Queen in the North. It's Sansa the politician vs. Arya the slit-your-face-off-and-wear-it assassin.

Tyrion and Davos sneak into Kings Landing — Tyrion to see Jaime, and Davos to find the last member of House Baratheon, King Robert's bastard son Gendry, whom we last saw in the Season 3 finale, when Davos loaded him in a rowboat and sent him off.

Tyrion surprises Jaime in the catacombs below Kings Landing, and in an earlier season we'd be treated here to a lengthy scene of Emmy-bait dialogue full of recrimination and regret, but there's no time, man. Tyrion starts to open up about their father, but Jaime barks at him to move it along already because there's only two episodes left.

Gendry and Davos make it back to the beach below Kings Landing but are waylaid by this week's Rosencrantz and Guildenstern. Davos turns on the charm — and the change purse — and bribes them with a little Westerosi gejang, but when the guards recognize Tyrion, it's Hammer Time (No Gendry/Don't hurt 'em/OK, wow, too late/Never mind/Looks like you hurt 'em/A lot.)

Jaime once again stops by Cersei's chamber, this time to inform her of Dany's desire for a meeting to discuss the White Shamblers, but this ain't Cersei's first zombie rodeo, and she knew about the whole thing. Turns out she's got some news for Jaime — she is expecting a lion cub, and what's more she's going to tell everyone who the father is, because she's the dang queen, and what are they gonna do? They embrace, but they do that television thing where they open their eyes when the other person can't see them, so we know they're both scheming. "Never betray me again," says Cersei. Jaime says nothing but darts his eyes like shiftiest shifter to ever shift a shift.

Snow bros

In the dragonglass mine, Davos introduces Jon Snow to Gendry, who sees no reason to keep his true parentage secret. There follows an exchange between the two young men that you keep expecting to break into high-fives, or at least a Bastard Bros 4Ever secret handshake. Gendry wants to accompany Jon on Mission: Zombie Show And Tell.

Jon takes his leave of Dragonstone, but not before bidding farewell and good luck to Dany. They share a moment that I think the show wants us to find sexually intriguing, but instead plays like a mom sending her kid off to ski camp.

Back at the Citadel, Sam is dutifully scrivening while Gilly reads him useless facts from the journals of an old High Septon named Maynard: the number of steps in the Citadel, the number of windows in the Great Sept, the fact that Jon Snow isn't a bastard at all but a trueborn Targaryen and rightful heir to the Iron Throne [record scratch].

Yep — that's what that annulment business was about. "Maynard says he issued an annulment to Prince Ragger [NOTE: That's Rhaegar Targaryen, son of the Mad King, father of Jon] and remarried him to someone else in a secret ceremony in Dorne." That someone was Lyanna Stark, meaning that Jon, as the heir to Rhaegar, has a better claim to the Iron Throne than Dany, Rhaegar's younger sister.

It's quite a little bombshell to lob, only to have a frustrated Sam ignore it out of frustration. He sneaks into the library one last time, grabs a few books from the forbidden section one last time and leaves the Citadel for good. This means we've likely seen the last of Jim Broadbent, which is a shame.

At Winterfell, Littlefinger is being dependably sneaky, but Arya is sneaking on him, too. She sees Winterfell's maester hand him a raven-message he's requested from the late Maester Lewin's extensive records. She sneaks into his room to find it, which makes very little in the way of sense because if he was so anxious to secure it, presumably to make sure no one else saw it, surely he'd just burn it, not squirrel it away in his mattress?

Arya finds the note — a copy of the message Sansa sent to Robb, telling him to (sing along, you know the words) bend the knee to Joffrey — and looks weirdly put out by it. Not sure why the show thinks it's so damning, when it makes more sense for Arya to assume, as Robb did when he received it, that Sansa was simply being coerced. Anyway, the seeds of discord have been sown, which we know because as Arya sneaks out of Littlefinger's room, the man himself is sneakily sneaking in the shadows, smiling a sneaky smile through his sneaky mustache.

Mangy Avengers, assemble!

Jon and company makes it to Eastwatch, where Tormund has captured The Hound, Beric Dondarrion and Thoros, who were headed north of the Wall to fight. Gendry resents them, of course, as it was they who sold him to Melisandre back in Season 3. Tormund resents Jorah, The Hound resents ... everybody. Whole lotta bad feelings to go around.

But Beric reminds them that they are all headed to the same place at the same time. Jon tells his fractious band of followers that they're all on the same side. Namely the side of not being rotting ambulatory corpses.

And so they set off together, this motley, beardy, doubtlessly stinky band of warriors, into the wilderness north of the Wall. They do not do this walking abreast, nor do they don sunglasses, and as they walk toward the camera nothing explodes behind them in slow motion which they then do not turn around to look at.

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