The title card reads "Minecraft Aftermath Let's Play S1E16 with BasketMC." It picks up right where the last episode stopped, partway down the spawner building. "Where were we? We cleared out that room and that room, just finished that room." Basket is still alone, still going floor by floor, and the description says a good part of this one runs at 1.5x speed too.
Finishing the floor
The routine from Part 1 holds. A torch goes into each room "just to slow down spawns," doorways get blocked, and water goes down the stairs to wash mobs toward the next floor. Basket calls it "maybe less fun, but more... less destruction." One room has a zombie spawner that sits still "because it's too light." The rooms give up leather, a compass and some planks. "Alright, this floor is complete."
The zombie in diamond armor
The floor below is crowded. "That's a lot of guys. This guy with the diamond armor will probably be difficult to kill." A few minutes later Basket decides "diamond helmet's pretty good." Night comes on while the water works its way down the hall.
A crowd on the roof
Then the zombies come all at once. "That's a lot of zombies. I wonder where they all just came from." A creeper goes off somewhere ("Let's see what that creeper did to my floor"), and the fight ends up out on the roof after dark, Basket swinging a diamond sword into a line of zombies between the torches. "Yeah, you guys just couldn't jump out the building."
Back inside, the damage is light, "just a little bit of floor stuff," and the best guess is that the mobs "spawned through the wall."
Creepers and holes in the floor
The next floors are more of the same, with creepers waiting in rooms. "Don't blow up right there. Jerk." "I lost my other water bucket." Basket keeps checking for holes ("No stupid holes in the floor") and notes, "My bows actually hold up better than my sword." One room already has a torch in it: "Oh, somebody was in here, look at that." Then: "that's ground level so there might be just one more below us."
The open floor
The ground floor is one big open room full of zombies, and the doorway plan does not fit it. "I guess they're confused by the water." Basket wishes for "a sharpness diamond sword" and for lava ("I think I need lava"), and in the end gives up on one spawner: "I'm just going to break that spawner, I think. Yep, we have plenty of other spawners."
Lava in the basement
With a lava bucket in hand, Basket sends lava across the lower floor, then torches go down. "Plug up these holes." "The basement actually didn't have a whole lot." "I was hoping for something super, super awesome." What it does have: "So we have creeper spawner."
"So this building is clear." The next step is to work out "good spots for setting up big spawner things," ask the others whether they want the building for anything, and maybe move the spawner setup to a spot with "like five or six spawners within range of each other." The episode ends on the end card, with no gameplay after it.