Rotten Gorge is a cave full of giant mushrooms, cobwebs and more zombies than anyone can count. They come out of it with the lime wool, a new sword and a pile of lapis. The emerald is another story.
Which emerald is this?
They start by a waterfall. One of them has already put two blocks in a gap so nothing can path to them. "I thought of everything." There's one emerald in this area, and there are creepers on top of the big brown mushroom.
A chest on a ledge has iron armor, arrows, golden apples and some beetroot junk. Then they follow the water and argue about numbers. Is this the way to emeralds 12 and 13? No, they decide, this is 14. "We did 10 and 11." They agree, and there's an ender chest here too. One of them keeps running ahead and gets told they're "being a very Scoti today."
Down the waterfall
They go down the water into a room of zombies and green mushrooms, with a record sitting in the middle. One of them is about to break a sword and didn't bring a backup. The other drops some spares, and then a zombie drops a sword anyway. "It was magic." There's also a hole with nether wart in it, which they still didn't have.
The zombies don't stop. Somebody keeps saying "you're doing great," which leads to a talk about The Amazing Race and cheering on a partner who's losing. The ask is simple: if I'm dying, come save me instead. "You're very lawful good. And I'm very chaotic good."
Basket's Titan Axe knocks a baby zombie straight up onto a mushroom. Poison spiders live in a webbed hole by one of the lakes. A chest of enchanted armor turns up, gold with Mending. A sign says a mushroom "has been grown with bonemeal. He is a real boy now."
The record turns out to be the Tune of Vitality, with Sharpness XIII. That sounds huge until they check the damage: 7, which they figure is still worse than a Sharpness II sword.
Lime wool
The emerald should be inside one of the big spongy mushrooms, they think. The biggest one has obsidian inside, and when they dig in, that's where the wool is. "I have a lime. Lime wool."
Uneasy Alliance
The zombies come in a crowd after that, along with fire from somewhere. "Oh my god, I thought I was gonna die." Basket's screen pops up a challenge, Uneasy Alliance, and nobody is sure what it was for.
Lapis and Silver Light
A dark corridor leads down to lapis, and a lot of it. A creeper spawner goes, a "pickaxe guy" drops a Fortune III wooden pickaxe, and a lapis golem drops lapis and Fortune III stone pickaxes. "Lapis, you're so square!"
A Grand Treasure Chest behind iron bars holds Silver Light, an iron sword with Sharpness III, Fire Aspect II, Looting III and Unbreaking I. It's part of the Veteran Set, like the Titan Axe. One of them had already called dibs, and it gets handed over. Now they have "the goodie sword."
Still no emerald
They have the wool. They don't have the emerald. Their best guess is the water or the webs, but there's a witch, more poison spiders and an inventory problem. One more chest has enchanted gold tools, so they wall themselves into a small room to combine and sort. One of them nearly throws out a diamond axe.
The axe needs repairing, so they head back. They'll come back for the emerald.