Team Flash finally find Caitlin's dad, but the reunion is less than a joyous one.
- Battle Boomerang: This is how Cicada kills the meta with the ability to turn her hands into blades, Raelene Sharp. She's about to finish him off when the dagger returns, disables her abilities, and stabs her in the back.
- Brain Bleach: when Ralph gets his nose twitching, Cecile calls it nasty.
- The Cameo: Thawne and DeVoe show up via Team Flash's picture circa Season 1 (specifically the one from "The Sound and the Fury") and security footage of the Speed Lab from when Killer Frost was suppressed, respectively.
- Death of Personality: Icicle's goal is to have Caitlin create a serum that will permanently remove his alter-ego, Thomas.
- The Dreaded: Ralph says that Cecile used to be this, having the In-Series Nickname of Ce-Seal-Your-Fate Horton among his previous peerage.
- The Empath: Cecile & Ralph realise that her powers have become empathy, which puts a hiccup in her attempt to investigate the FEMA center as she channels the attendant, who's guilty of embezzling the insurance claims of its patients, and thus fumbles her intimidation since she's feeling his fear.
- "Eureka!" Moment: Caitlin acknowledges Cisco is right about her father when she realizes that the serum he is about to be injected with would destroy the human side of a metahuman.
- Fighting from the Inside: Thomas is trying to suppress Icicle, but fails.
- Foreshadowing: Caitlin's dad mentions Batman villain Victor Fries, yet another nod to the upcoming Elseworlds (2018).
- He's Back!: Killer Frost finally comes back just in time to stop Icicle from killing her friends.
- Huge Guy, Tiny Girl: While not a couple, we get to see a lot of the spectacular height difference between Hartley Sawyer and Danielle Nicolet, including Cecile climbing onto the couch to yell at Ralph.
- Hyde Plays Jekyll: From the moment Caitlin, Barry and Cisco find him, "Thomas" is in reality Icicle trying to gain their trust.
- "I Know You're in There Somewhere" Fight: Sadly, it doesn't work and Icicle gets away.
- It's All My Fault: Naturally, Caitlin blames herself when her dad gets away.
- Jumped at the Call: Cecile is obviously bored of staying home so much and is happy to join Ralph in his investigation.
- Kryptonite Factor: The climax of Caitlin's subplot takes place in a room approaching absolute zero temperatures, so Flash and XS lose their speed the moment they arrive.
- Like Parent, Like Child: Both Caitlin and her father developed a villainous Alter Ego with ice-based powers after their cryogenic therapy against ALS.
- Mythology Gag:
- "Thomas" mentions Louise Lincoln, another identity of Killer Frost in the comics.
- Killer Frost was held back by mental blocks. This thread was also brought up (in this case with Wally West) in The Return of Barry Allen storyline.
- Odd Couple: Caitlin notes how her mom and dad are total opposites, musing how on earth they got along.
- Popcultural Osmosis Failure: Cecille doesn't know who Deanna Troi is.
- The Power of Hate: Cicada is horribly injured, but refuses to be treated, as the pain apparently provides him with more strength for his mad quest.
- Properly Paranoid: Cisco doesn't trust Thomas' cover story, believing there to be too many holes and he manages to get Barry and later Caitlin to share his concerns; he's right as Thomas has been taken over by his split personality — Icicle — and wanted Caitlin's medical expertise to create a serum that would suppress Thomas.
- Rebuilt Pedestal: Downplayed but Caitlin warms up to her mother a little after seeing how devious Icicle can be, realizing she was genuinely trying to protect her from him.
- The Reveal:
- Caitlin's powers never came from the Particle Accelerator Explosion. As a child she inherited her dad's ALS, and he treated her with experimental cryogenic therapy which resulted in her split personality of Killer Frost; Thomas has one too — Icicle.
- DeVoe used Brainstorm's powers to suppress Killer Frost, not Melting Point's.
- We finally learn Cicada's name, motivation, and source of his powers — his name is Orlin Dwyer and his daughter Grace was put into a coma thanks to debris from the satellite, which injured and gave him his dagger — and he blames all the metas in Central City for her condition, which is why he's hunting them down one by one.
- Shapeshifter Weapon: Raelene Sharp, the meta Cicada kills in the episode's first scene, was able to turn her arms into razor-sharp blades.
- Sharing a Body: After realizing that she still has Killer Frost and that her power loss was just a mental block, Caitlin uses Harry's Cerebral Inhibitor, modified for Electronic Telepathy, for live communication with Killer Frost.
- Surprisingly Realistic Outcome: When Cecile asks the FEMA director for a list of names of people who've received help she's told she needs a warrant for that information.
- Third Line, Some Waiting: The episode has three running plots with the group split up to tackle each of them. Ralph and Cecile investigate the FEMA center that was set up after the Enlightenment to find if anyone matching Cicada's profile was treated there. Iris, Nora, and Sherloque investigate possible places where Sally the satellite's dark matter-rich core crashed, as its shrapnel is the most likely to have become Cicada's dagger. Finally, Caitlin, Barry, and Cisco follow up on a lead on her father.
- Too Much Information: Sherloque telling Iris and Nora that he has had constipation since arriving on Earth-1.
- Villain: Exit, Stage Left: Icicle manages to escape.
- We Can Rule Together: Icicle offers this to Killer Frost, but she declines, fully cementing her Heel–Face Turn.
- You Have to Believe Me!: Initially, Caitlin isn't buying Cisco's warning about her father.
