For Alyssa Rosenberg’s review of this episode, click here. Here are the five biggest takeaways from Sunday’s action-packed, Walker-filled episode.

1. The White Walkers have arrived
The White Walkers storyline lingers over the entirety of “Game of Thrones.” In theory, it’s the most important part of the show and the GoT universe, the ultimate battle between the living and the dead that makes all that jockeying for the Iron Throne seem downright quaint. Littlefinger’s political machinations are great and all, but it’s hard to scheme your way through a zombie apocalypse. There are no deals to be cut with the undead. In practice, thought, the blue-eyed killers show up and wreak havoc just about once every season; what keeps us watching week after week is the palace intrigue that involves characters we’re emotionally invested in and who have actual names.

For the watchers on the couch who enjoy the fantasy element of GoT above all, then Sunday’s episode was an instant classic. There’s no denying it was a visual marvel, the sort of blow-HBO’s-mega-budget episode that happens once a year, reminiscent of season 2’s “Blackwater” or last year’s “The Watchers on the Wall.” I mean, there was a giant stomping zombies to death and swatting others away like he was playing whack-a-mole. That was awesome. You ain’t gonna see that on “Halt and Catch Fire.”

How did we get to the big battle? Jon Snow took his calculated risk, leaving The Wall and sailing with Tormund to Hardhome, the closest thing to a true wildling settlement. Upon arrival, they are greeted by Lord of Bones, who always seemed more bark than bite, as if he was hiding some weakness behind that gnarly mask of his. Bonesy doesn’t approve of the fact that Jon and Tormund have teamed up, crows and wildings fighting together. But Tormund doesn’t approve of this disapproval and quickly turns the Lord of Bones into a lifeless pile of bones. That’s a strong way to make an entrance.

Now it’s time to sell the rest of the wildlings on this proposed new alliance. During his pitch, Jon says they’re not friends and won’t become friends but this is not about friendship, it’s about survival. In the eyes of the White Walkers, there’s no distinction between crows and wildlings, every body is just more meat for their army. Jon seems to be gaining support until Mance Rayder’s name comes up and someone thinks to ask, well now that you mention him, where is Mance? Jon says he’s dead, thanks to an arrow he put into his heart.

This results in much grousing, which Jon had to expect, because was that really the best way to put that? He leaves it to Tormund to explain that actually, Jon’s arrow was a show of mercy. Tormund vouches for him — “he’s prettier than both my daughters but he knows how to fight” — and it looks like we might have a full-on alliance. Except for the Thenns. Don’t count them in. It’s never easy with the Thenns. Very difficult clan.

But there are bigger worries than Thenns. Soon the dogs start barking, the wind starts howling and the snow starts swirling. By god, that’s the White Walkers music! From there it’s 20 minutes of mayhem and no description will really do it justice. Some highlights, though:

  • The 4 Horsemen of the Walkers observe from the mountaintop as their skeleton army attacks.
  • Main White Walker dude easily takes out Disagreeable Thenn before being shattered to pieces by Jon Snow and his sword, Longclaw. Does this mean Valyrian steel, in addition to dragon glass, can also bring down the undead?
  • New Main White Walker dude locks in on Jon Snow and either thinks, 1) that’s the guy I need to make sure to take care of, or 2) he is thinking nothing at all because he’s undead
  • Karsi, (aka Agreeable Female Wildling) meets her demise at the hands of some Child Walkers
  • It would be nice if there was more than one giant to do some stomping and swatting
  • How cool was it when New Main White Walker raised his hands to resurrect the freshly killed wildlings and bring them back to sorta-life as Walkers?
  • Shouldn’t Jon, Tormund and company be paddling a little faster to escape the zombie army that is standing a few hundred yards away from them?

2. Tyrion is officially on board as an advisor to Daenerys
Back amongst the living, Daenerys and Tyrion get to know each other in Meereen. Daenerys starts off with some basic and accusatory questions — How do I know who you are? Why shouldn’t I kill you? — but they eventually begin to form a bond. Dany’s first test for Tyrion is asking him what should become of Jorah Mormont; she swore she would kill him if he ever returned, so should she follow through with that threat? This is the kind of situation that Tyrion has a knack for expertly negotiating and he manages to walk the fine line in the way that he always does. Tyrion says that Jorah’s life is worth sparing, as a ruler who kills those devoted to her does not inspire devotion. But he cannot simply be allowed to stay by her side. Dany listens to Tyrion’s advice and tearfully banishes Jorah, once again. Jorah, who is still hiding his greyscale infection, quietly accepts his punishment.

Dany decides to keep Tyrion as an advisor, but Tyrion’s first bit of official advice is somewhat surprising. Maybe you don’t want to sit on the Iron Throne, he suggests. “There’s more to the world than Westeros,” he says. This idea doesn’t gain much traction with Dany, but Tyrion is worried that Dany doesn’t have enough friends in high places to make a proper run at the Throne. In terms of support, the Targaryens are gone, the Starks are gone, the Lannisters and Stannis are non-starters and the Tyrells probably won’t be enough. But Dany scoffs at this list of powerful houses, these spokes on a wheel. Those families that have traded power for centuries by playing their political games. Dany is done with games and isn’t just going to stop the wheel; she’s going to break the wheel. First breaker of chains; now breaker of wheel.

This new combination of characters — including two of the show’s most compelling — and Daenerys’s revitalized focus on becoming a worldwide conqueror and the potential battles in her future serve as a nice balance to the much more straightforward battle of living vs. dead that took up much of the rest of the episode.

3. Cersei could use a glass of water, let alone wine
Things are not going well for Cersei as a prisoner underneath the Red Keep in King’s Landing. She’s dirty and barefoot, if not quite broken, remaining defiant in the face of the charges brought against her. Qyburn informs her that these include fornication, treason and the murder of King Robert, which sounds like not a bad way to spend a weekend. Qyburn is worried that the Faith does not adhere to the same standards of proof as the crown when it comes to guilt and gently suggests that Cersei simply confess to her sins and be absolved. Maybe then she’d get a decent meal instead of being left to slurp spilled water out of the cracks of a filthy floor for sustenance.

Perhaps after a little more convincing, but for now Cersei is going to pass on kneeling before “some barefooted commoner and beg his forgiveness.” Qyburn isn’t too surprised at her refusal and on his exit he informs her that “the work continues.” What is this mysterious “work”? Is it turning The Mountain into even-more-vicious Frankenstein Mountain?

4. Sansa finds out she’s not the last surviving Stark
In miserable Winterfell, miserable Reek brings miserable Sansa some food which gives her a perfect chance to chew him out for telling Ramsay about her attempts to communicate for outside help. Reek tells Sansa that there simply is no escaping; Theon Greyjoy tried to escape but Ramsay found out and cut away piece after piece until there was no Theon left. Sansa’s like, well that’s the first reasonable thing Ramsay’s ever done and she would do the same right now.

As Reek runs down his list of failures — turning on Robb, capturing Winterfell, killing “those boys” — Sansa gets enraged at him calling her brothers, Bran and Rickon, “those boys.” But then Reek comes clean and admits “those boys” he killed and charred to a crisp were two farmer’s boys, not the Stark children. This is the best news she’s received in forever, which kind of puts into perspective how bad it is to be Sansa. Even her good news — she has family that’s still alive — involves the brutal murder of innocent children.

5. Arya trains to become a sociopath
What exactly is Arya learning how to do in the House of Black and White? Before she can become No One, she has to become someone else, we get this. Apparently this someone else is an orphan named Lana who sells oysters, clams and cockles. Is she working to become a mystical assassin or just your run-of-the-mill grifter who invents a new identity to get one over on a sketchy gambler? Wasn’t this Sawyer’s storyline from “Lost”?

Line of the night: “The f— you looking at?” The Giant, to Edd