Tropes:
- Apocalypse How: Planetary/Total Extinction of Earth. Not even the fish survived. Moclus has also been destroyed, as well as half of all biological life in the galaxy.
- Attack Drone: The Kaylon in the alternate timeline are able to launch their heads as attack drones, granting them air superiority against the resistance forces.
- Back for the Finale: Season finale, anyway, but nonetheless, Alara shows up as the leader of a resistance unit in the alternate timeline.
- Bad Future: In the alternate timeline, the Kaylon have wiped out half the galaxy.
- Butterfly of Doom: This is the second straight season finale where Kelly falls victim to this. Kelly choosing not to go on a date with Ed meant that she never cared enough for him to get him the captaincy on the Orville. Because he was never captain, Dr. Finn never joined the crew. Because she never joined the crew, Isaac never formed an attachment to her and her sons. Without that attachment, Isaac never changed sides and the Kaylons disassembled him, leaving no one to thwart their invasion of Earth.
- Call-Back:
- Alternate Alara mentions that she's been taking gravity treatments to keep her strength, which was introduced in "Home".
- Ed asks Talla to open a "jar of pickles" for him, referring to a stuck door, something he used to keep asking Alara to do in Season 1. Then again, this version of Ed doesn't know that.
- Remember "Nothing Left On Earth Excepting Fishes," and the conversation that led to that Title Drop? Yeah, in this timeline, the Kaylon wiped out all life on Earth and the crew specifically notes that this includes all sea life as well.
- Alternate Claire states that she always likes to be posted where she's needed. In the premiere episode, Claire stated that she always requests her transfers based on where she thinks she's needed.
- Darker and Edgier: To say the episode didn't pull any punches would be an understatement.
- The Determinator: Bortus has managed to stay alive for several months on an Orville that's been stuck on the bottom of the ocean, subsisting on combat rations and the hope that he'll get to see his family again.
- Detonation Moon: Apparently, the Kaylon have cracked the Moon open during their attack on Earth. Based on the enormous craters on the planet, it appears some of the chunks have fallen on Earth or were tossed there by the Kaylon.
- Didn't Think This Through: Kelly herself lampshades how she failed to take into account the far-reaching effects on everyone that would occur without her and Ed ever being married. Ed even reminded her she took courses in Temporal Law about this sort of hypothesis, and in an earlier episode, it was her present version who explained to Gordon how her ability to cross a single eye was the result of her past relationship with Ed along with everyone else being currently being on the Orville.
- Evil vs. Evil: It's mentioned that the Kaylon and the Calivon are pretty much deadlocked, and haven't yet engaged each other.
- Explosive Overclocking: Unlike the prime timeline Orville, the damaged Orville can't handle the power strain of the time device and explodes, though it holds out long enough for Claire to make it back in time.
- Going Down with the Ship: Bortus went down with the Orville after the captain and first officer were killed, giving everyone else time to Abandon Ship. He survived the crash and has been living on the Orville ever since, sustained by the hope that he might one day make it back to Moclus and reunite with his family.
- Good News, Bad News: John has a plan to Set Right What Once Went Wrong by accessing the Kaylon network to download Isaac's data and complete his calculations on the temporal device. That's the good news. The bad news is that Isaac acts as a homing beacon for the Kaylons to pinpoint the Orville's exact location, and they have to shut down the quantum drive to activate it.
- Heroic Sacrifice: The resistance cell led by Alara and Yaphit stay behind to cover the escape of Ed and the others, leading to their deaths when the base explodes.
- Imperial Stormtrooper Marksmanship Academy: The Kaylon in the beginning of the episode spend several minutes firing on and missing two middle-aged men struggling through the snow. Even when one trips and the other has to stop to pick him up, the advanced killer robots still can't hit them.
- La Résistance: The Kaylon believes that it doesn't exist anymore. That's exactly what they wanted them to think.
- Literary Allusion Title: The episode's title refers to the poem of the same name by Robert Frost.
- Mundane Wish: Gordon and Ed finally get a replicator after months of looking, and sit down for an honest meal. Obviously, Gordon's first request is a Twinkie.
- Nice Job Breaking It, Hero: Kelly tried to spare herself and Ed the pain of their failed relationship. Instead, she doomed the galaxy.
- Not Hyperbole: Considering that her deciding not to be with Ed is the nail that led to the extinction of all life on Earth, Ed is right to tell this to Kelly:Ed: I thought you ghosting me was the end of the world. Turns out I was right.
- Not So Above It All: Mercer criticizes Gordon for using the replicator to make a Twinkie, until Gordon offers him half and he happily accepts.
- Orgasmically Delicious: Ed is incredulous that the first thing Gordon gets out of their stolen replicator is a Twinkie. Until Gordon gives him half. Then, they both invoke this trope.
- Reset-Button Suicide Mission: The whole idea behind the crew's plan. If they can send Claire back to do a more thorough mind wipe of Young Kelly, then this Bad Future won't come about. And they know it's a suicide mission no matter what because their only method to do so leaves them sitting ducks with a "shoot here" beacon for the Kaylon.
- Resistance Is Futile: When John taps into the Kaylon network to download Isaac's consciousness into a defunct Kaylon shell, Isaac gloats about his superior intelligence and tells him to just give up and die.
- Ret-Gone: When Claire applies the memory wipe to Kelly's past self, she and the entire bad timeline are wiped from existence.
- Set Right What Once Went Wrong: Kelly gathers the crew so she can fix her mistake and set the timeline back to what it once was.
- Shipshape Shipwreck: The Orville in the Bad Future is in remarkably good shape, considering it was badly damaged in battle, crashed into the ocean, and sunk to the bottom of the Mariana Trench. The latter part is the worst, because even with full deflectors the shuttle they use to reach the ship is almost destroyed, and the Orville has been down there for 9 months on minimal power. The ship should have been crushed like an aluminum can in a hydraulic press. The bar is even intact with intact bottles of alcohol, and when they power up the ship everything works normally, and no damage is discussed. It's particularly notable that they are able to drain the flooded shuttle bay and establish normal pressure (1 atm), when the pressure on the ship is 1071 atm. A simple Hand Wave about emergency deflectors keeping the ship intact would've been sufficient.
- Likewise, the ship becomes fully operational again in a very short amount of time despite the damage it took, although this could be due to Bortus lacking the technical knowledge to make the repairs.
- Shout-Out:
- Flying into an Asteroid Thicket to escape enemy fighters? Where have we seen this before?
- At the resistance base, Yaphit opens a small hole in the door and pokes his mouth out on a stalk. This mimics the eyestalk droid security system seen in several Star Wars media, starting with Return of the Jedi.
- The Resistance outpost looks like a cross of the Yavin base in A New Hope and the Endor base in Return of the Jedi
- Continuing the Star Wars references, the banged up, blaster scorched, barely lit Orville at the bottom of the ocean creaking ominously under the water pressure brings to mind the Hrakert Rift Research Station.
- The Bad Future's ending in the titular ship having to overload its engine core while under attack in order to help Set Right What Once Went Wrong is reminiscent of the Star Trek: Enterprise episode "Twilight".
- Taking You with Me: The resistance base explodes shortly after the Kaylon breach the door. Based on Alara's comment earlier about the Kaylon wanting prisoners, it is likely that the resistance self-destructed their base to safeguard information and wipe out whatever Kaylons they could.
- Unrealistic Black Hole: While they're right about the idea of time dilation, they don't show it to the extent that it would be in real life. They also escape the event horizon without using FTL drive, which goes against the very definition of an event horizon.
- What the Hell, Hero?: Ed calls Kelly out for deciding on her own to change history by not dating him, even citing the Temporal Law course at Union Academy on not messing with the timeline. Kelly is forced to take it, knowing he's right.Ed: I thought you ghosting me was the end of the world. Turns out I was right.
- World of Silence: The characters can't find a single sign of life on Earth, even deep in the Marianas Trench. "The Kaylon were thorough" indeed.
- You Shall Not Pass!: Alara and the rest of La Résistance fight the Kaylon so that Mercer, Kelly, and their team can escape.
