"My name is Nora West-Allen, the fastest woman alive. When I'm from, thirty years from now, I'm the guardian of Central City. I'm a speedster, just like my dad. People call me XS. Every day, I hope to live up to the legacy of the Flash but I've still got a long way to go."
— Nora's Opening Monologue
While the Team deals with a Meta named Gridlock, Barry and Iris struggle when their future daughter, Nora, comes into their lives...and her claims of being stuck in the past. Meanwhile, Ralph assists Caitlin with trying to restore Killer Frost, investigates her background, and discovers some surprising information from her past.
- Aesop Amnesia: Barry deciding to keep Nora in the present (or from her perspective, the past) to prevent his disappearance in 2024 shows that he hasn't really learned anything from Flashpoint.
- Arson, Murder, and Jaywalking: Ralph's samples of the changes in his manyverse: one where everyone's evil note , another where there's no world hunger, and lastly one where the last Indiana Jones film was never made.
- Atrocious Alias: Cisco doesn't think too highly of Nora's codename.
- But Now I Must Go: Wally leaves to "find himself."
- Call-Back:
- When speaking to Iris, Barry says "Nora shouldn't be here", a phrase he uttered verbatim the previous year.
- When wearing the tachyon device, Nora is excited about wearing the same device her father wore when first meeting Supergirl.
- Cisco previously expressed an interest in seeing a King Shark vs. Gorilla Grodd duel, but prohibits Nora from describing the details. He probably wanted to witness the fight firsthand.
- Barry repeats Thawne's instruction on how to use phasing powers to Nora.
- The Call Knows Where You Live: Discussed by Joe and Wally, as it's noted that Wally's journey of self-discovery that he set out on a year earlier was cut short when he was dragged into the Legends' battle with Mallus.
- The Cameo: Tom Cavanagh makes an appearance prior to his official return this season, as Barry has a flashback to Eobard Thawne when coaching Nora how to phase, repeating him word-for-word from "Tricksters".
- Cosmic Deadline: The Flash's time as a superhero seems fated to end in April 2024, where he disappears in the midst of a crisis and never returns.
- Discontinuity Nod: In a sense. To back up his understanding of time travel and alternate timelines, Ralph makes a comment about how changing the timeline could result in a world where he died because of the Particle Accelerator explosion — this was, in fact, Ralph's original fate prior to the timeline changing because of Flashpoint and Barry's subsequent attempt to undo it.
- Drama-Preserving Handicap: The only reason Nora doesn’t identify Gridlock immediately is because Mr. Miles the Flash Museum curator had the names of the Rogues scrubbed for legal reasons.
- Drowning My Sorrows: Cisco is still depressed about Gypsy breaking up with him and is clearly in a hangover throughout the episode.
- "Eureka!" Moment: When talking about how great parents they want to be, Barry realizes that Nora is here because she never really knew them as great parents.
- Failed a Spot Check: This is the first time Barry (or any member of Team Flash) has realized the implications of the headline on Thawne's newspaper from 2024, having previously only taken note of Barry's costume changing or the name of the article's writer.
- Flashback Echo: When Barry tells Nora how to phase, he flashes back to Thawne doing the same thing for him and repeats the lines as he remembers them.
- Foreshadowing: Nora mentions that King Shark would fight against Grodd to protect Central City, but Cisco made her stop.
- Funny Background Event: When Ralph was preparing to explain his "manyverse" theory, Cisco is readying a Face Palm. For the rest of Ralph's exposition, Cisco does indeed bury his face in his hand, and stays that way.
- Here We Go Again!: Joe has this reaction after Cecile reveals she may not have lost all of her telepathic abilities by perfectly understanding the needs of her crying infant daughter.
- I Just Want to Be Normal: Barry reveals to Iris that he wishes that raising a child would be the one normal thing about his life, and having a daughter from the future puts a nip in that.
- I Was Just Joking: After being told that negative tachyons are a thing, Cisco guesses that they slow you down instead of speeding you up. He says this line after seeing Wally’s face.
- Immediate Sequel: The episode takes place minutes after the last finale, in contrast to the usual Time Skip.
- Internal Reveal:
- Barry learns that Nora is the speedster who helped him destroy the S.T.A.R. Labs satellite.
- Barry finally finds out what the audience has known for the last four years — he disappears in the Red Sky Crisis in 2024 and never comes back...
- Ralph tries catching up on the multiversal and time travelling shenanigans the others have been through before he joined the team. He also learns about Killer Frost being gone since DeVoe's attack. Lampshaded by him complaining about nobody ever telling him anything.
- Played for Laughs when the team somehow learns about the S.T.A.R. Labs lounge just now, which only Joe and Nora were privy to beforehand.
- Wally tells Nora and Joe a few of his adventures with the Legends, like when he met Elvis.
- It's All My Fault: Nora notes that in her timeline, Gridlock was "one and done" as Barry defeated him during their initial encounter — but her presence led to Gridlock being able to escape.
- Jerkass Ball: Barry keeps his distance from Nora because he doesn't want to screw up the timeline (again).
- Killed Offscreen: The show ends just as Cicada prepares to kill Gridlock with his dagger.
- Leaning on the Fourth Wall: Cisco stops Nora from revealing too much information of a Grodd and King Shark duel by shouting out "Spoilers!"
- Leitmotif: As the two watch with a sense of yearning and pride while their grown daughter hangs around with her uncle and cuddles up with her grandfather, "Come Home to Me" can be heard in the background as Barry holds Iris in his arms, that's tinged with a slight note of sadness as Barry has learned from Nora there may come a day when he may not be able to come home to his wife and daughter.
- Let Me Get This Straight...: Everyone's reaction after Nora tells everybody who she is, with Cisco in particular getting a refill.
- Logical Latecomer: Ralph is understandably frustrated how he's new to the whole time travel and multiverse thing.
- Locked Out of the Loop: Ralph finally learns just how much comic book weirdness he's been missing out on. Even the mention of Harry being from Earth-2 went over his head as he thought they were just saying he was "from Earth too" (as in, also from Earth). Becomes a bit of a Running Gag throughout the episode.
- Mythology Gag:
- Nora uses the word "schway", the Future Slang term for "cool" which originated from Batman Beyond.
- The Flash ring that Nora gives to Barry was created by Ryan Choi, the successor of Ray Palmer as The Atom in the comics.
- Gridlock is technically a Flash rogue, having fought Impulse in the comics.
- The scene where the speedsters have to phase the plane through a building is taken straight from the New 52 Flash series. Nora also mentions Mob Rule, the villain of the issue where it occurred.
- Nora mentions Lightning Lad while talking with Iris, a founding member of the Legion of Super-Heroes that XS is a member of.
- Ralph tracks down the identity of the coroner that signed Caitlin's father's death certificate as Cameron Mahkent, the civilian identity of The Icicle.
- Nora's other newspaper (dating 25 years after Thawne's own article) states that after the Red Sky Crisis, Barry has yet to return. That almost comes close to the duration of Comic Barry's disappearance after the Crisis on Infinite Earths.
- Cisco calling Nora out on revealing details from the future, calling them spoilers. This is Impulse's Catchphrase in Young Justice (2010).
- Never Trust a Trailer: The trailers used Nora's "Total fan favorite" line to tease the Flash ring and Barry's new costume — the line is instead referring to Barry's original costume from the first season.
- Nice Job Breaking It, Hero: Nora going to help Barry against Gridlock exposes Barry to an attack by Gridlock that sends him to a lake.
- No Good Deed Goes Unpunished: Nora helping her dad stop the satellite supposedly stranded her in the past. At least, it seems that way until Barry finds out that that she’s only stuck because she has a device keeping her from being sent home.
- Offscreen Moment of Awesome: Ralph goes off on a little sleuthing adventure on his own, and picks up an important clue to Caitlin's suddenly-Mysterious Past.
- Parental Neglect: Nora reveals that after Barry vanished, her mom was always distant towards her.
- Pop-Cultural Osmosis Failure: When Barry states that Nora could "Marty McFly" herself out of existence, Iris incorrectly identifies Marty as the protagonist of Terminator 2.
- Properly Paranoid: Barry is understandably very worried about what having his future daughter around could mean for the timeline.
- Put on a Bus: Wally, again, leaves for a journey to find himself.
- The Reveal:
- Barry disappeared a few years after Nora was born, but she was too young to remember him. She came back in time for a chance to see her dad, and faked being stuck in the past for a chance to know him better.
- The death certificate of Caitlin Snow's father is a forgery.
- Ridiculous Future Inflation: In 2048, coffee at Jitters costs $43. Nora finds the more reasonable prices of the present an improvement by comparison.
- Right for the Wrong Reasons: When Nora is running in the Speed Lab, Barry initially believes that Nora is lying about who she is, while Iris believes that Nora isn't. It turns out that they’re both right — Nora is in fact Barry and Iris's daughter, and she does have negative tachyons preventing her from traveling back to her own time. What Nora doesn't mention is that she has a device that is putting them into her system that she can turn off whenever she wants, which would allow her to travel through time.
- Set Right What Once Went Wrong: In her closing voiceover, Nora states that her ultimate goal is to change the future and prevent Barry from disappearing in 2024.
- Shock and Awe: Gridlock's way of releasing his kinetic energy.
- Stating the Simple Solution: Barry states that if Nora can't build up enough speed to go back to the future, he can always have Wally call the Legends to bring her home. After Wally has the Waverider Gideon run some tests on Nora's blood, it's revealed they can't help since Nora's body is contaminated with negative tachyons which. Wally describes these as being like antimatter to the ship's time drive, meaning Nora can't use any kind of time travel.
- The Stinger: Cicada, the new Big Bad, intercepts the police convoy carrying Gridlock to prison in order to kill him.
- Time Skip: Averted — for the first time in the entire Arrowverse, a season premiere starts immediately after the previous season's finale rather than picking up a few months later.
- Truth in Television: Cecille keeping at least some of her powers after giving birth. In Real Life, a woman's body undergoes many changes during pregnancy. There have even been cases of lifetime allergies being "cured" during pregnancies, which sometimes don't return even after the pregnancy.
- Wham Episode: Barry finds out about the Red Sky Crisis, which according to history (as of Nora's departure) he never returns from.
- Wham Shot: The headline on Nora's newspaper feed:"25 Years Later—Flash Still Missing"
- Who's on First?: Ralph assumed that when the team was saying that Harry is from Earth-2, he thought they meant Harry was also from Earth.
- Worf Had the Flu: Without the S.T.A.R. Labs satellite, Team Flash has trouble keeping tabs on metas. They wouldn't even know that a metahuman has struck until after the act he/she committed.
- You Can't Fight Fate: Played for Laughs. Nora tells the team that the villain of the week is called Gridlock, a name she knows from the archives of the Flash Museum in the future. Cisco doesn't care much for the name. Later, during a conversation about the meta's powers, Cisco inadvertently ends up coming up with the name "Gridlock" for him, realizing that he was the one who named the villain after all!
- You Can't Go Home Again: Nora's DNA is saturated with negative tachyons which means she can't enter the Speed Force and setting foot on the Waverider would fry the ship's time drive, so she can't travel though time at all. Subverted in that Nora's only stuck in 2018 because she had a device that was actively putting the negative tachyons into her system.
"My name is Nora West-Allen, and I'm the fastest woman alive! When I was a child, my father disappeared in something impossible...then I grew up and became the impossible! Now I'm trying to live up to the legacy he created, so that one day, I'll stop him from disappearing. I'm XS! How schway is that!?!"
— Nora's Closing Monologue
