Sorry that I've been skipping so many episodes. I either wasn't interested in that episode or I just couldn't find a way for Isabella to fit into the plot.
Peridot is seen about to give a presentation to the Gems, "Ahem, ahem. As it seems I have no other options, I have conceded to reveal some important information to you Crystal Gems." she snaps her fingers, cuing Steven to shuffle in, wearing a box with a box with a crudely drawn picture of Earth on it. Peridot, using a flyswatter as a pointer, smacks the box, making Steven teeter in surprise, "This... Is the Earth. At the very center of the planet's core lies... the Cluster! Rotate." Steven complies, turning the box to show a representation of the Earth's core and the Cluster inside as Peridot points at the illustration, "This is the Cluster. A massive, artificial fusion composed of millions of Gem shards. It has laid dormant for thousands of years within this planet's crust. When this Gem activates and takes its form, the result will be catastrophic. Now!" she hits the box again.
Steven turns back to the Earth picture and bobs up and down, making escalating noises. A green snake-like puppet then bursts through the box, making the Gems and Isabella gasp.
"BWAAAAAAAAAAAAAAAAAAH!"
"What is that!?" Peridot asks.
Steven speaks with the puppet, "It's the Cluster."
Peridot swats the puppet with the flyswatter, "It does not look like that. But it is real, and it can activate at any moment!"
"Bwaaaah."
"What a cluster." Amethyst says.
"That abomination must be stopped." Garnet told them.
"But how?" Pearl asks, "We'll need to build some sort of machine to take us to the center of the Earth, it'll have to-"
Peridot suddenly swats at Pearl and interrupts her, "Hey! I wasn't finished speaking! What we need is to build some sort of machine to take us to the center of the Earth." Pearl glares at Peridot in annoyance as Amethyst looks at Pearl and smiles sarcastically. Pearl then glares at Amethyst, causing her to stop, "It'll need to withstand up to 360 gigapascals of pressure and temperatures of 9800 degrees."
"Well, we mustn't waste time. We need to start finding parts for this machine immediately." Pearl speaks.
"Yes. Obviously. We'll start by dismantling all devices inside this dwelling." Peridot runs to the kitchen and grabs the microwave, "This primitive radiation concentrator should come in handy!" she tears the microwave off the cupboard and throws it on the counter. She then grabs a corded phone from the living room, "This primitive vibration transmitter could possibly serve a function!" Peridot smashes the dials on the table, splitting it in half. She then runs up to Steven's room and lifts up the television, "There's a remote chance something useful could be inside this primitive image cube!" she smashes the TV on the floor.
"Wait a minute. Instead of destroying all of our electronics, we could just use some parts from the barn." Isabella suggests.
The siblings bring Pearl and Peridot to the barn, and Peridot inspects it form the outside.
"All right. What we have here in the barn should be adequate enough for us to get started. First, I recommend we organize the component types and assemble a rough blueprint based off what we have available."
