They make camp on a cliff. Samwell wants to babble about the First Men, thousands and thousands of years ago, who stood there through the Long Night. No one cares. Snow looks at some weird-looking clouds in the distance. There's another horn blast. Snow says, "One blast is for rangers returning. Two blasts is for wildlings." Samwell elaborates that one is for friends, two for foes, and three for white walkers. That one hasn't been used in a long time, but Sam read it in a book, which everyone treats with weary, bemused contempt.
Tyrion looks at a jar of green liquid. I guess someone's discovered the secret of creating purest green. That would be the old creepy guy over here, who assures him that the substance burns wood, stone, steel, and flesh. "It melts flesh like tallow!" After the dragons went away, it was key to Targaryen dominance. Bronn is skeptical of all these claims, since he's seen lots of pig shit get called Wildfire. Old Guy insists that it's not pig shit. I believe him, because if your pig shit is bright green, you have some very sick pigs. The plan is to load these jars of supposed wildfire into catapults and thus destroy any incoming fleets. Bronn thinks catapults need to be manned by real soldiers, most of whom are out on the battlefield. And even with proper soldiers, battles are chaotic situations and bottles get knocked over. And if the stuff in the jars is as powerful as the older gentleman is claiming, that would be bad. Except he says all this much more rudely, which draws this response: "You would not dare insult my order while Aerys Targaryen lived!" Bronn shrugs and says the wildfire didn't help Aerys much. In his opinion, men win wars, not magic tricks. Tyrion is let into a storage room where there are allegedly 7,811 pots. The whole order has been working tirelessly. Bronn: "This is a shit idea. Tyrion calls the old guy Wisdom Hallyne, and I would have appreciated it if that could have been worked in earlier in the scene. Tyrion says, "The contents of this room could lay Kings Landing low. You won't be making wildfire for my sister any longer. You'll be making it for me." I don't get the impression that Wisdom cares who he makes wildfire for. Some men just want to see King's Landing burn.