Original airdate: January 6th, 2016
Production code: 1031-076
And peace and war on the planet Earth
With the Gem drill nearing completion, all that's left is finding the coordinates of the Cluster's location. To access it, the Gems hop on Lion's back for a trip to an ancient Diamond base on the moon. However, tensions grow between Peridot and the Crystal Gems when they discover the initial plans for Earth's colonization...
- Admiring the Abomination: Peridot is amazed at the Homeworld's original plans for Earth, while the Crystal Gems are horrified.
- All for Nothing: Peridot claims that Rose's campaign to protect the Earth caused Homeworld to test the Cluster on Earth instead of making a colony world. She has a point, since it's only because Peridot isn't willing to die with the Earth that they even knew about it.
- Allohistorical Allusion: Some of the locations of gem sites shown on the map correspond to places where extra-terrestrial phenomena supposedly occurred in real life. The Beta Kindergarten the Cluster is located under seems to be in the approximate location of Area 51. In the approximate location of The Tunguska Event, there's a gem site surrounded by an ocean that's not present in real life.
- Berserk Button: Peridot hits the Crystal Gems' button HARD when she says Rose Quartz "ruined everything." They all give her a dark, angry expression and Garnet comes very close to destroying her.
- California is the site of another Gem Kindergarten, probably explaining why the equivalent of Hollywood in Steven's version of Earth is actually located in Kansas.
- The catalog of Gem structures that Peridot brings up includes the Lunar Sea Spire, the Ancient Sky Arena, the Sea Shrine, the Sky Spire, the Communication Hub, and the Galaxy Warp.
- It turns out Peridot's description of feet as "gravity connectors" is more apt than we thought, as gems' bodies automatically adjust to varying gravity.
- Character Development: Subverted. While Peridot has undergone some small development and has become fond of the Crystal Gems, this episode reminds the viewers (and Steven) that the ideals that were instilled in her by Homeworld can't be overcome in a few weeks.
- Cliffhanger: Steven sees Peridot silently grab an object from the moon base of unknown purpose.
- Compliment Backfire: Peridot reveals that the Cluster is rooted in a Beta Kindergarten that is not as "great" as Amethyst's Kindergarten. Amethyst is not amused, but semi-sarcastically takes the compliment.
- Continuity Nod: Among the Gem structures that Peridot shows when accessing the moon base files are some that the Gems have visited in previous episodes.
- The Cuckoolander Was Right: Peridot calls the Gem Leadership the "Great Diamond Authority", and shows that the Gem colonization of Earth would have hollowed out the planet, both exactly what Ronaldo claimed at the end of "Keep Beach City Weird".
- Culture Clash: Peridot is impressed by the original plans to colonize Earth. The Crystal Gems are not.
- Death Glare:
- Garnet stares down Peridot when she says that the Gems serve the Diamond Authority. Peridot clarifies that they were made for that purpose and some choose not to.
- The Gems give an utterly terrifying glare to Peridot for blaming Rose Quartz for Earth's upcoming doom.
- Disappointed in You: Steven is crushed that Peridot hasn't come to care for the Earth the way he and the Crystal Gems have.
- Double-Meaning Title: "It Could've Been Great" is Peridot's Title Drop about the abandoned Gem colony, but it also describes Peridot's growing relationship with the Gems and Steven that undergoes a setback.
- Downer Ending: Peridot's progress with befriending the Crystal Gems is torpedoed when she starts gushing over the colony world Earth could have been, indirectly insulting everything Rose Quartz accomplished, fought and sacrificed for. Even Steven is infuriated by what she's done, and he's suspicious when he sees her walking off with a crystal she took from the console.
- The Empire: Peridot officially confirms that Homeworld is the center of a still-growing interstellar empire.
- Facepalm: Steven shoves his hand in his face as Peridot gushes about the potential colony, not getting why the gems would disapprove.
- Galactic Conqueror: Peridot says the diamonds made all of the gems to expand their empire across space.
- Hard-Work Montage: The Gems finish up the drill in a montage while singing Steven's song.
- Heroic RRoD: Lion collapses for a long nap after getting the Gems, Peridot and Steven to the moon.
- Hope Spot: For Steven, Peridot singing and bonding with the Gems seems to mean she's come to love the Earth. Then she reminds him she's a Homeworld gem by admiring the plans for the Gem colony.
- Hostile Terraforming: The Gems' colonization of Earth would have essentially gutted the planet and made it uninhabitable for anything other than Gems. Hell, they managed to do a serious number on the planet◊ even before the Rebellion drove them off.
- I Hate Past Me: Earth's terraforming, while horrifying to Steven and Amethyst, should have come as no shock to Pearl or Garnet. The two older Gems would have been perfectly aware of what happens to planets when Gems change them. What they're probably being reminded of, via Peridot's tin ear, is what they used to be, and to an extent still are: aliens who see other life forms as beneath them.
- Humans Are Insects: Peridot tries to argue that the planned Earth Colony could've given birth to countless Gems and helped expand their empire at the cost of a single planet, only to have it thrown back at her by the Crystal Gems due to the fact that it would've wiped out all of the indigenous life on the planet for the sake of potential Gems, not already existing ones.
- Insignificant Blue Planet: The fact that Earth would've been destroyed to create a Gem colony doesn't bother Peridot in the least, much to the immense chagrin of the Crystal Gems since it would've destroyed all life on Earth. Which begs an interesting question: was there existing life on other worlds before they became Gem colonies?
- Jerkass Has a Point: While Peridot was in the wrong for disrespecting Rose in front of the Crystal Gems, she was technically right that the rebellion only inspired the creation of the Cluster and merely delayed Earth's destruction.
- The Knights Who Say "Squee!": Peridot is thrilled to find out she's walking in the footsteps of the Diamonds.
- When Steven tells Peridot to sing along with the (musical) key during "Peace and Love (On Planet Earth)", she pulls out a (door) key in confusion.
- Steven says that it feels like yesterday when Peridot was trying to kill them. Pearl says that was several weeks ago.
- Measuring the Marigolds: Peridot tries to logically analyze the simple solfage that Steven teachers her, before trying to write a song herself. She ends up enjoying herself anyway, which ends up allowing her to bond with the Gems.Peridot: I suppose it's just interest... Do-mi-so-do. Devoid of substance or purpose, a hypothetical pattern... Do-mi-so-ti. For the satisfaction of bringing it to completion.
Peridot: Do-mi-so-ti. Interest without meaning? Solutions without problems?
Steven: And then you add words.
- Moral Myopia: Peridot doesn't care at all that all life on the planet would've been destroyed had the Rebellion not defeated the Homeworld, or that the only reason it's in trouble now is the Homeworld's doing. Her only concern is for all the Gems that could have been born on the colony, as well as the expansion of their empire.
- Multistage Teleport: To get to the moon, Lion has to create portals while inside his portals over and over again.
- Mundane Made Awesome: The floor of the gem base forms a floating staircase that leads the data that the Gems need. As Steven notes, the Diamonds "really like stairs".
- Musicalis Interruptus: After Peridot enrages Garnet, Amethyst, and Pearl, Steven tries to calm them by reprising the song from earlier in the episode, but he's just ignored and shoved out of the way.
- Not So Above It All: When Steven sits in the command chair, Peridot is furious he'd sit where greatness would. However, she's quickly encouraged to sit beside him, which puts her into a fit of giggles.
- Not Worth Killing: Steven convinces Garnet to hold off on attacking Peridot by pleading that "It's not worth it".
- O.O.C. Is Serious Business: Steven is almost as furious over Peridot insulting Rose as the Gems are. When Steven is pissed off by what you've done, you know you've screwed up royally.
- Overly Long Scream: Peridot screams for nearly twenty seconds straight when the gang is riding on Lion.
- Percussive Therapy: After Steven talks Garnet out of responding to Peridot's disparaging remarks with violence, she decides to just crush the console that was displaying Homeworld's plans for Earth.
- Remember That You Trust Me: Inverted. Just as the Gems seem to bond with Peridot, she undoes weeks of Fire-Forged Friends by saying that Rose's efforts were All for Nothing.
- Seat Of Power: Steven sits in the Diamond command chair, and gets Peridot to join him.
- Sequel Hook: Peridot takes something back from the Moonbase, and only Steven sees her. What is it? Well, we'll have to find out in Message Recieved.
- Skewed Priorities: Steven tries to get a sleeping Lion to warp them to the Diamond moon base by telling him all the things that would be destroyed by the Cluster. Lion only responds when he says "no more naps."
- Space Base: The diamond base on the moon.
- Space Episode: Taking place on the moon.
- Speak Ill of the Dead: Peridot says all of Rose's work was pointless and didn't save anything in front of her companions and son.
- Spreading Disaster Map Graphic: The Diamond Authority's simulation of Earth's colonization looks like a cell being devoured from the inside by a virus, and ends up filled with spiky, crystalline formations and completely hollowed out except for supports attaching the mantle to the core. Chillingly, it's shown that the process wasn't entirely prevented, as there's a gargantuan hole in the Asian continent even before the simulation is activated, and the structures of South America, Africa and Australia are vastly different as well.
- Tempting Fate: Steven talks about all the progress Peridot has made right before the plan to go to the moon base.
- Title Drop: Peridot really likes the simulated Earth colony.Peridot: What were you thinking in shutting this operation down? It could've been great!
- Undying Loyalty: Peridot can't stop gushing about the Diamonds, suggesting that some kind of cult of personality is in place.
- The Unreveal:
- Peridot shows Steven the murals of Blue Diamond and Yellow Diamond, but skips on the other two. They pass by the mural of White Diamond on the way up, but Pink Diamond goes unseen.
- On the way to the control room, they pass by a room with a floating blue orb in the center. Garnet will only say that it's not what they came for.
- Verbal Backspace: Peridot says that all Gems serve the Diamonds before a Death Glare from Garnet makes her clarify that they are merely made to serve the Diamonds but not all Gems do.
- Watching the Sunset: Garnet, Amethyst and Pearl stop working on the drill to watch a sunset, aggravating Peridot who sees nothing special about it.Peridot: Why are they just sitting there looking at nothing?!
- What the Hell, Hero?: Steven gives a quiet condemnation to Peridot at the end of the episode about how he's disappointed that she doesn't see how the world is important and denigrating their centuries of protecting the Earth.
- Wingding Eyes: Steven's eyes reflect the finished drill as he admires it and the moon when he realizes that the diamond base is up there.
- Yank the Dog's Chain: For Steven, he thinks that finally Peridot is learning to love the Earth, especially when she starts singing with him and the Gems. Then when they go to the moon, Peridot can't let go of her Homeworld roots or prejudices so easily.
- You're Insane!: Steven encourages Peridot to write a song about anything she thinks of. Peridot makes a song about being stuck with the Crystal Gems.