Episode 4 of Season 1 is a stream that opens on Cycle 10, where Episode 3 stopped, with six duplicants and Fine Dining being researched. Over this video a Compost goes in, the farm turns out to be too hot, a seventh duplicant joins and a refrigerator gets built. It ends on Cycle 13 with the colony out of power.
A stinky corner
The commentary starts with a tour: the duplicants run on wheels for power, carbon dioxide is settling at the bottom of the base, and Bubbles is the most stressed. Research gets priority 6 so that Fine Dining finishes sooner, "cuz I want refrigeration." More floor is dug out for planters.
Then comes the idea that names the episode: "Oh, compost would be a good thing to do." The spot has to be one where nobody minds the smell, so it goes by the outhouses, "because they're already stinky themselves." It is meant to take the polluted dirt and turn it into fertilizer. During the stream, two duplicants are renamed, and the commentary notices the Jobs screen keeps the old names.
Too hot to grow
A plant on the farm floor is unhappy. Oxygen is fine, but the temperature overlay shows the trouble: "it is too hot over on this side." There is no way to cool it yet. "Maybe after we do some more researching it'll be possible." Food has started to rot too, and the game shows a Rotten Mush Bar waiting to be swept. Storage fills up, so more goes in by the batteries, and the duplicants fill it almost at once.
Ren and the refrigerator
Fine Dining finishes, and new food buildings show up in the menu. A new duplicant is picked: Ren, a Level 13 Runner with +13 Athletics and the trait Can't Dig It. A refrigerator goes on the floor above, with power run up through the floor, where the commentary plans a kitchen. "Fridge is now up and running."
Gas pipes
On the research screen, the Thermo Regulator catches the commentary's eye: it cools gas but puts out heat nearby. Gas Piping is picked, "I wanna try and make those crops grow well." A Massage Table is placed for the stressed duplicants. Once the research is done, floor tiles are swapped for Gas Permeable Tiles so oxygen can rise through the base, while the outhouse corner is kept separate.
Where it ends
The last job is a small room for rotten food and polluted dirt, with a wall, an airlock door and storage bins. Then the power runs out: "You guys didn't generate enough power. Maybe we should get some extra batteries going." The video ends there, on Cycle 13.