Tyrion finds Sansa. She's moping. She's kind of always moping, but this time it's clear that she's heard about Robb and Catelyn. He turns and walks away. She resumes the mopery.
Bran's crew finds an empty castle. I'm so jealous of all these empty castles around the place. There's a well, which is providing Hodor some innocent enjoyment. It turns out that if you like hearing things echo, the word "HODOR!" is fairly resonant. Bran tells him to knock it off. Then he explains that he's nervous because there are a lot of stories about this place. Jojen likes horrible stories, so he encourages him to continue. Bran's story concerns a cook in the Night's Watch. When the king was visiting the Nightfort, the cook killed his son and served him in a pie. The king liked it so much that he asked for a second slice. So the gods turned the cook into a giant white rat that could only eat its own young. And it still roams the Nightfort, because that's the sort of thing you do when you've been cursed by the gods. Meera mocks the idea that the gods would go to the trouble of cursing someone just for being a murderer. Bran says it was for killing a guest under his roof, which is "something the gods can't forgive." First, note that this is apparently the Nightfort, which is the place that Sam and Gilly were headed for. Second, we know someone who just recently killed a guest under his roof. That's quite a coincidence!
And speaking of Walder Frey, here he is! He's eating in his bloodstained dining hall, although he has servants trying to scrub the floors. Roose Bolton is listening to Walder brag about how well his ambush went. This also gives Walder the opportunity to drop some exposition about how Edmure spent his wedding night in a dungeon. The Blackfish escaped, but Walder doesn't care about one old Tully. He's got Tywin Lannister on his side, and now he's Lord of Riverrun. He segues into the general topic of how everyone looks down on him: "People snigger when I marry a young girl, but who said a word when Jon Arryn married that little Tully bitch?" Roose points out that he probably needs a new young girl. Roose says Robb ignored his advice at every turn, so he feels no second thoughts about betraying the self-proclaimed "young wolf." Roose says he might move to Winterfell after the war, although it's in ruins right now. Walder asks what exactly happened up there, since after all the ravens got killed, nobody heard anything. Roose says he sent his bastard to root out Theon. They told the gang that sacked Winterfell that Robb Stark offered amnesty if they gave us Theon. And the Ironborn turned on Theon. Roose says, "They handed him over, trussed and hooded. But Ramsay...Ramsay has his own way of doing things."