Varys comes in and compliments them on the marked drop in thievery. Bronn explains that they rounded up all the known thieves. Tyrion asks, "For questioning?" Bronn: "Um... no." So now it's just the unknown thieves they need to worry about. Bronn says that in a siege, it's the starving that kills people. Early on, the poor start eating each other. But the thieves love sieges. As soon as the doors close, they steal all the food. Then all the rich people trade everything they have for food. And when the doors open, the thieves are rich. To avoid this situation, Bronn has killed all the thieves he could find. I guess I applaud him for a forward-thinking, proactive plan.
Varys admires Tyrion's book about the great sieges of Westeros. And he pronounces the name of the author correctly, which is probably a purposeful dig at Tyrion. Tyrion comments that Stannis knows the city and knows what gates are weakest. He decides that the Mud Gate is where Stannis will most likely attack. Bronn suggests that they could throw books at Stannis. Tyrion says they do have a lot of one asset: pig shit.
Samwell and the other Night's Watch men dig a latrine trench. I'm kind of surprised we're going back to them; I thought we'd just be following Jon Snow when we went north of the Wall. Sam wonders where Snow is. The cynical answer: "A betting man would go with dead." Sam can't imagine that, because after all, "He's got a Valyrian steel sword!" More cynical answer: "So did his father." Apparently, great rangers don't get old. And neither do the shit ones. This is mostly just banter, but I wanted to point out that again that the only type of steel anyone talks about is Valyrian. It's supposed to be rare and strong, but it seems like it's all over the place. While digging, they uncover something with some symbols on it. Oh shit! They found a hatch! No, wait. It's just a stone. Sam says the First Men made those marks, so he wants the stone. He's very into the First Men. He's kind of the Game of Thrones equivalent of somebody in our world who's really into Game of Thrones. They get the stone out of the ground. And in the hole underneath it, there's something wrapped in a Night's Watch cloak. There's a fancy horn and something Sam calls "dragon glass." Although he clarifies that to be "obsidian" and I appreciate him using real-world terms. I suppose he learned that word in one of his fancy books.