HBO: This episodes features two calls to arm – Grey Worm to the people of Meereen, and Jon Snow to his brothers to join him at Craster’s.

Bryan Cogman: Up until this season, you didn’t find yourself writing too many speeches for Jon Snow. But he’s really stepping into a leadership mode, bringing a lot of what he’s learned from his experience and his mistakes. These middle episodes, which I generally end up writing, are a lot about introducing plot threads that pay off later. That’s what a lot of the Castle Black stuff is here, the going beyond the Wall, Locke’s ulterior mission to find Bran and Rickon, and there’s a reference to the "choosing.” I don’t believe we addressed yet that Lord Commanders are elected. For Alliser Thorne, Acting Commander, it’s really his Alexander Haig moment, for those readers who are familiar with ‘80s presidential history. He’s basically said: We’re at war, I’m in charge, we’ll deal with the election later. That dynamic between Jon and Thorne is great to go back to. We haven’t had Alliser since Season 1.

The Grey Worm scene was challenging in a unique way. In the writers’ room, Dan [Weiss] and David [Benioff] came up with the idea that Dany decides to empower the slaves to take their own city. Having Grey Worm step up and showcase him in the first part of episode was cool. I believe it’s the first time a scene has been entirely in Valyrian – not that I had to write the dialogue in Valyrian. Language creator David Peterson writes that.

HBO: Moving north to Craster’s Keep, why do the wives chant “a gift for the gods”?

Bryan Cogman: If you’re at Craster’s Keep, you stay alive by making a deal with the White Walkers. It followed that the mutineers were going to have to make a choice – run or keep this bizarre transaction going. These women, who had lived under the thumb of their father-husband, were taught to worship White Walkers as “gods." It gives you an idea what was going on all these years.

That sequence to this day was the hardest to write for the show. It’s not in the books – you have mutineers and Craster’s, but their fate is somewhat different in the book and also, it happens off the page. And it’s a very ugly sequence: They’ve taken over Craster’s and made it even worse than it was.

We’ve paid a lot of lip service to idea that Night’s Watch is made up of shady characters, rapists and thieves, but we never saw much of that. The mutiny was the beginning. This is the worst of the worst finally free of the shackles of society.

HBO: And it’s all happening under Karl.

Bryan Cogman: The original idea for Karl was more of a Colonel Kurtz-‘Apocalypse Now’ situation. The guys and I worked really hard on second draft and made it more about class, how this man feels he had a raw deal his entire life, and how he has real contempt for upper classes and society. He’s also very dangerous and probably a psychopath. So if he has a kingdom of his own, what would a guy like that do?

For Karl to function, he needs weaker people to intimidate and do his dirty work. Although Rast is no saint, you see a glimmer of morality, and some kind of guilt for what’s going on. But he’s in so deep he can’t get out of it, and he’s also scared.

HBO: What can you tell us about the wife who brings in the baby?

Bryan Cogman: The original idea behind Morag was that she was the first of the daughters who became Craster’s wife. So she’s the prime wife, if you will, and the matriarchal figure for these women. She knows she can’t fight these mutineers and knows that without them, the White Walkers could destroy the wives. So there’s a lot going on. And then you throw in Bran and Hodor, two of the most endearing characters. To have to write a scene where Hodor gets bear-baited and beat up was just miserable. But the idea was to put Bran, Hodor, Jojen and Meera into a really dangerous situation beyond the Wall that didn’t involve the supernatural, but rather humanity at its worst.

HBO: Another major turning point in the episode is Olenna’s lesson to Margaery. We get a glimpse of her passing the torch.

Bryan Cogman: I love the Olenna-Margaery dynamic. When Diana [Rigg] joined the cast, I remember looking at an old publicity shot for ‘The Avengers’ – not the Robert Downey Jr. movie but the 1960s spy show – I thought, she’s the Natalie Dormer of her era. In our version of the story, Olenna was Margaery in her day and Margaery will be one day be Olenna. It was a scene not unlike Sansa and Littlefinger’s, so it’s two tutor-protégé scenes back to back. Olenna is illustrating to Margaery what she has to do next through a personal story. That was based on a nugget that [author] George [R. R. Martin] has in the book; Olenna, in an entirely different scene says: Oh, I was engaged to a Targaryen once, but I got out of it. The Dany storyline can seem so far removed, so whenever you can thread in that the Targaryens were the family once in power, the better.

HBO: And then Margaery applies what she learned.

Bryan Cogman: Then you go into the Tommen, Margaery and Ser Pounce scene. In the book he was a kitten but I arrive on set, and they’ve cast a sumo wrestler cat. This is probably the last time you’ll see Ser Pounce because filming with a cat is a nightmare. Natalie Dormer wanted to kill me. But the cat is in it because he serves a purpose: You immediately see that Tommen is not Joffrey. Tommen is a sweet boy with a cat named Ser Pounce, and who has found himself in incredible circumstances. He is going to be king and he is going to marry this woman. The innocence of Tommen is fun to play with because there isn’t a lot of innocence in this world.