Episode 130 opens on the Minecraft 1.12.2 title screen and drops straight onto the city wall around Basketopia. Some work happened off camera: the inside and outside of the wall are finished, a lot of the top has gone on, and Basket ran the whole length putting torches in the bottom of the hollow wall so nothing spawns inside it.
Slabs, stairs and a curve
The top of the wall gets a layer of stone brick slabs across the whole thing. Where the wall climbs gently, slabs are enough. Where it gets steep, Basket switches to full stairs. The trouble spots are the diagonals, where the stairs have to "curve in" toward the slope and the levels need adjusting a block at a time. Basket tries the stairs sticking out into the path, then tucked in, and settles on tucked in. Battlements will go on the outer side later, with cobblestone fences on the inside along the flat parts. Basket had forgotten the fences and starts adding them.
Goodbye, cow
Running low on blocks, Basket comes to a big wool build sitting where the wall needs to go. "Goodbye cow." The shears come out and the wool comes down, block by block. A viewer suggests saving the wool for decorating the shops, and Basket likes that, so it goes into storage. Getting across takes an ender pearl, and Basket notes it is the last one.
Shopping under the castle
The stone is underneath the castle, in a big cavern that has already been dug out, with chests, a Nether portal and a beacon on a pyramid. Basket stocks up on stone and explains the rules for anyone who wants to dig down there: anything below the ground can go, but don't break through the surface, don't dig so close to the ocean floor that the gravel caves in, and watch out for a lava ravine. Any spawners should be left alone, because Basket wants to build them into the rooms planned down there. The beacon is set to speed and could be switched to haste.
Up the steep part
Back at the wall, near where a gatehouse will eventually go, comes the stretch Basket calls the one "where it gets a little crazy." The plan was to rise in threes, but the slope is too quick, so the wall goes up one block at a time and then levels off. On a gentler run nearby the steps drop to every two, with slabs on top.
A viewer suggests a race around the top of the wall. Basket is up for it, and thinks it would not take long. Another viewer suggests doing it on pigs. Basket then remembers the wall does not quite go all the way around: the big harbors and one other gap mean a racer would have to swim in a couple of spots.
Ten high to the tower
The last stretch runs toward the spot for a "pretty massive tower." Asked whether the wall keeps people out or in, Basket says both: invaders stay out, and people already inside can't just climb onto it. Basket counts each section to ten blocks high, steps it up one at a time, runs out of blocks, restocks and keeps going until the line meets the top. A quick look from below shows the wall coming up small toward the empty tower spot, which will make more sense once the tower and another gatehouse are built. The credits run to the end with no gameplay after them.