Sherloque orders up a memory machine for Team Flash to wake up Grace, but Nora is afraid that the machine could inadvertently reveal her secret relationship with Thawne to her parents, so she tries to use it leaving her trapped, and Iris and Barry have to come in to rescue her and end up in Nora's brain instead.
- All for Nothing: The plan to wake Grace up since Nora discovers to her horror that she shares her uncle's anti-meta views and sees him as a hero and Flash and XS as the villains.
- Alone with the Psycho: Nora trapped in Grace's mindscape with both Grace herself (revealed to have become a Creepy Child) and a mental projection of Cicada.
- Animated Armor: An animated version of the Reverse-Flash outfit displayed in The Flash Museum is the form of the defense mechanism of Nora's subconsciousness. It can also speak, and in some shots a body actually wearing the suit is clearly visible as well.
- Bad Future: In Nora's future (even in a version where she changed the timeline) not only did Flash not stop Cicada, he also never stopped killing — which put a black mark on the Flash's legacy.
- Bait-and-Switch:
- Ralph's supposed informant on Cicada is really talking about a band named Sickada.
- When Sherloque says that Nora didn't want anybody to find out about her secret, he looks as if he knows about her connection to Thawne, but then he just refers to her bad memory of Iris.
- Chekhov's Gun: Both the CCPD and Flash Museum memories having phones on hand, the latter getting mentioned as part of the merchandise. Caitlin and Sherloque use the M.A.D. 2.0 to communicate with Nora, Barry and Iris using these phones.
- Continuity Nod:
- Barry mentions the Thinker in regards to having experience with a Journey to the Center of the Mind.
- Lots in the Flash museum, of course. Also, Iris uses the Thinker's chair to teleport an enemy away once more.
- Creepy Child: Grace has become this while in the coma, thanks to soaking up Dr. Ambres and Orlin's anti-meta rhetoric, wanting to hide the truth about her home life and the dark matter shrapnel in her brain which is manifesting itself in her subconsciouses as an avatar of Cicada, heavily implying that Cicada is a Legacy Character and she's the second one.
- Dark Secret: Nora does not want her parents to find out that Eobard Thawne is her mentor, let alone she's been in constant contact with him.
- Daddy's Little Villain: Well, uncle in this case, but it's revealed that not only does Grace know about her uncle's actions, but she approves of them because she feels the same way he does about metas.
- Didn't Think This Through: Nora just entering the memory machine alone puts her and later her parents in grave danger.
- Diegetic Soundtrack Usage: The Flash phones in the Flash Museum have a chiptune version of the show's theme melody as their ring tone.
- "Eureka!" Moment: Cisco realizes how he can get the genetic information he needs to produce the metahuman cure when Kamilla, the bartender he's talking to, offhandedly mentions her sister.
- Foreshadowing:
- The Flash Museum states that not only was Cicada never caught, but he also kept on killing. Then at the episode's climax an avatar of Cicada manifests itself in Grace's subconscious as a defense mechanism to drive Nora out. But after she and her parents leaves, it stays there heavily implying Grace will become Cicada II.
- When we first see Grace in Orlin's kitchen in her subconsciousness, there are towering stacks of pancakes and waffles that Orlin has made for them both, despite the audience knowing from previous flashbacks that Orlin was the kind of person who fed his niece a takeout container of leftover Chinese food, which is our first clue that something isn't right in the memories—they're exaggerated, being created from a child's point of view.
- Freeze-Frame Bonus: The Cicada who fights Nora at the end appears to be a woman in the outfit from the brief glimpses we get of the eyes and hair, implying Grace is going to grow up to take over the mantle (and is possibly the reason he's still considered at large in the future).
- From a Certain Point of View: Caitlin is surprised about Ralph's non-existent ice skating skills, as he previously told them that he practically grew up on the ice - his mother dated a zamboni driver named Doug.
- Future Me Scares Me: Iris is appalled at how her future self treats a ten-year-old Nora, especially how she forbids her to come to the Flash Museum — the poor thing just wants her dad and all Iris does is yell at her. Small wonder Nora spent most of the first half of the season hating her mom; of course, this is all from the perspective of a sad, angry child and the true memory isn't anything like this, it's just a defense mechanism of Nora's subconscious. In reality, Iris gently chastises her daughter and is much more understanding and nurturing.
- Futureshadowing: Similar to Abra Kadabra mentioning Savitar, Zoom, Reverse-Flash, and the then-unknown DeVoe, we get a "Hall of Villains" with costumes, data, and news reports on all sorts of Flash rogues, and the roster includes many past ones, the current Big Bad, and...huh, who's the Red Death? Presumably, our heroes won't like the answer when the time comes.
- In the Flash museum scene there's a Flash action figure with Superman, Batman, Green Lantern and Aquaman illustrations at the packaging. Both Batman and Superman are confirmed to exist in the Arrowverse, however Green Lantern has only been slightly referenced with Aquaman rarely having references in the Arrowverse. This might imply that in the future the four heroes along with Flash will become public to the world.
- Also, Superman is an Earth-38 hero, someone you'd not expect to be well known here on Earth-1. Just in case you forgot that a Crisis on Infinite Earths adaptation is coming...
- Godzilla Threshold: Caitlin and Cisco are adamant that their metahuman cure never be administered involuntarily, but given how nothing can stop Cicada — Killer Frost's powers can at best delay him, and Grace can't be counted on to talk her uncle down — Barry concludes that the cure is their only option to stopping him.
- Internal Reveal: Grace, who has been listening in on conversations happening at her bedside despite being comatose, is able to deduce that Nora is the daughter of The Flash.
- It Only Works Once: The team can't use the memory machine on Grace again, as the shard in her brain has now put up a barrier. Not that Grace would let them help her anyway.
- Jerkass Realization: At the end of the episode, Nora apologizes to her mother for having been so cold towards her and for holding her in a false, bad memory.
- Legacy Character: It isn't outright said, but there's enough clues in play to suggest the reason why Cicada is still killing metas in Nora's time is because Grace is Cicada by then.
- Mood Whiplash: Barry's seriousness at being trapped in Nora's memories turns to glee when he sees the Flash Museum, and then the mood becomes extremely sober when he sees a ten year old Nora sulking in the corner looking forlorn at an action-figure of the Flash.
- Morality Pet: Subverted. Team Flash initially believe Grace will be this for Cicada if they can bring her out of her coma, but when they try it's revealed that she knows about and approves of what he's doing. Ultimately she hates metas too much to accept their help anyway, so the team resorts to another plan.
- Mythology Gag:
- Sherloque helped track down the Batman rogue Jervis Tetch, the Mad Hatter, on Earth-221.
- He also refers to using the memory machine on coma victims at the Summerholt Institute. Summerholt was a neurological research centre in Smallville which specialised in memory manipulation.
- Sherloque also had his own version of Watson, called Watsune. He was unfortunately found braindead after using the memory machine alone.
- In the Flash museum, there is a comic issue on display showing Cicada's comic self.
- The memory machine was taken to Earth-1 by Forerunner Multiversal Delivery. In Countdown to Final Crisis, the Forerunners were the Monitors' scouting parties.
- Nice Job Breaking It, Hero: Subverted, although going in alone was extremely foolish it did allow Nora to find out that Grace shares her uncle's anti-meta views and she's too far gone to be reasoned with.
- The Reveal: Even though she's in a coma, Grace can still listen in on Orlin and Dr. Ambres' conversations — and she's soaking up their anti-meta rhetoric; the seed's been there since her parents were killed by a meta, and they've just nurtured it into full-blown hatred.
- Secret-Keeper: When he reveals near the end that Nora's been keeping a secret from Barry and Iris, Sherloque (who most certainly has at the very least almost figured out what it is) covers for her and says the thing she was hiding was her lingering negative feelings towards Iris.
- Self-Serving Memory: A rather upsetting version. Nora's memory of Iris reprimanding her at the Flash Museum has her practically snarling at her daughter and forbidding her from being at the museum. As we soon come to realize, this is not how it happened; Iris was being gentle with Nora, but Nora's lingering negative feelings warped the narrative.
- Serial Killer: In the future, Cicada's bodycount amounts to a whopping 152 and rising! To put it in perspective, Captain Singh says that he killed even more people than Zoom!
- Start My Own: Iris is planning to start her own Newspaper. Turns out it's the one that article from the future is from.
- Unreliable Expositor: Nora's true memories show that Future!Iris wasn't the harsh, draconian parent that she had previously claimed. Nora's resentment toward her mother colored her memories of their relationship.
- Wham Shot:
- The piece of shrapnel in Grace's head glowing like Cicada's dagger.
- When Nora is fighting Cicada towards the very end of the episode, we can clearly see it's not Orlin in the outfit, but someone with long, blonde hair note .
- What the Hell, Hero?: Cisco is pretty pissed when he realizes that Ralph set him up to accompany him to a date night instead of gathering intel on Cicada.
- Whole-Plot Reference: This Episode could be considered one to the movie Inception.
- You Are Better Than You Think You Are: Barry towards Iris, when he realizes that his wife was never as bad as Nora remembers her as.
- You Can't Fight Fate: Iris is distressed that the future hasn't seemed to change while in Nora's memories — the paper that reports the Flash's disappearance, The Central City Citizen, is the paper that Iris wants to found; she legally can't use any other name. But at the end, she is pleasantly surprised that the future can be changed when she learns the Citizen was originally founded two years later.
- Your Mind Makes It Real: Dying inside the memory machine means dying in the real world.
