When a nuclear bomb detonates in downtown Central City, Barry, Jay and Jesse use the Speed Force to slow down time. They now must work within a single millisecond to save the city.
Tropes
- Ambiguous Situation: The question is asked how Veronica Dale learned about the secret transport of a nuclear device and the suggestion is made that DeVoe leaked it to her, but there's doubt about it because they can't figure out what would be in it for him, and if it was truly him isn't answered in the episode.
- Badass Normal: Veronica Dale has no powers or abilities, yet still proves to be one of the most dangerous foes The Flash has ever faced.
- The Bus Came Back:
- Jay and Jesse both return from their Earths.
- The mysterious waitress from Barry and Iris' wedding again appears.
- Call-Back:
- Barry can stop time to talk to his friends. Previously he did this to dissuade Iris from exposing him as The Flash.
- One of Harry's memories of his (unnamed) wife is her saying "in the vast night sky, you are the only star I see", which is what Tess Morgan of Earth 1 said to her Harrison Wells, before they were killed by Thawne. It's also how the name "S.T.A.R. Labs" came to be. This implies that Harry's wife was a doppelganger of Tess Morgan.
- Character Development: By discouraging Jessie's idea of using Time Travel to stop the bomb from ever detonating, he demonstrates how he has truly learned his lesson from Season Three about its possible negative consequences.
- Chekhov's Gun: The Quark Sphere that was used as a decoy by Team Flash to help free Barry from the Speed Force was actually what they needed to stop the blast.
- Chekhov's Skill: Barry's ability to stop time is the technique used to stop Veronica Dale, and even finally gets an official moniker from Cisco: Flashtime.
- Color-Coded for Your Convenience: Exposition from Cisco describes the nuclear reaction as starting off blue, turning yellow, then becoming purple as it progresses, giving a rough estimate of how much time is left to solve it.
- Comic-Book Movies Don't Use Codenames: Veronica Dale is never once referred to by her comic-book moniker "Hyrax".
- Dented Iron: Jay may be able to move and heal faster, but he's still old and it wears him out a lot. In the end, he decides it's best if he retires from being a superhero.
- Despair Event Horizon: After every theory and attempt to dispose of the bomb falls flat, Barry, exhausted and hopeless, believes there is no way to save the city.
- Distinction Without a Difference: When Jesse accuses Harry of dodging the pain of his wife's death by leaving, Harry answers that he came to stop DeVoe. Jesse answers that he stayed on Earth-1 because of DeVoe, and Harry quotes this trope in response.
- Eco-Terrorist: Veronica Dale, who wants to make a point about how nuclear energy is bad...by blowing up Central City with a nuclear bomb.
- Electronic Telepathy: At the end of the episode, Harry modifies the telepathy blocker he created for Cecile and uses it to send his own thoughts and memories of his wife to Jesse.
- "Eureka!" Moment:
- When Jesse said that it would take more than the two of the speedsters to work on the bomb, Barry gets the idea to have her go to Earth-3 and call in Jay.
- Jay's sweat gives him the idea of cooling the bomb down, but non-speedsters like Caitlin cannot use their powers in Flashtime.
- Barry calling Iris his lightning rod gets her to realize how the quark sphere can be used to stop the nuclear explosion.
- Feeling Their Age: The continued Flashtime takes a heavy toll on Jay due to his age and is unable to help Barry and Jesse with a lightning throw as a result.
- Godzilla Threshold: Defied. Even in such an extreme situation Barry is still unwilling to Time Travel to prevent the disaster due to the possible negative consequences. Similarly, Jay is adamant against the idea of throwing the bomb into the Speed Force due to the possibility of destroying it completely.
- Gondor Calls for Aid: Jesse calls Jay to help out.
- Heroic Willpower: Barry's willpower is at its absolute peak this episode.
- Just in Time: Harry tells Barry that one way to neutralize the blast would be to send it into the Speed Force, just as Jesse arrives with Jay in tow, the latter of whom immediately opposes the idea.
- Internal Reveal: Barry finally learns from Iris that a Quark Sphere was sent to the Speed Force so Team Flash can free Barry.
- Leaning on the Fourth Wall: Killer Frost tells Flash "Don't let Caity die" referring to her host Caitlin Snow, though this could also be a nod to Katie Cassidy and Caity Lotz's character's deaths through the Arrowverse shows.
- Locked Out of the Loop: Apparently Barry was never briefed on how Team Flash was able to pull him out of the Speed Force.
- Long Game: After learning that DeVoe's been active for the last three years, the team speculates that everything that's happened this season has been part of a plan that's been in motion for just as long.
- The Lost Lenore: The reason Harry is such a bitter person? He never got over the death of his wife.
- Manly Tears: Downplayed with Harry, who cries after remembering his dead wife.
- Nice Job Breaking It, Hero: Discussed. Jay tells Barry that the idea he and Harry have about sending the bomb to the Speed Force is terrible, since it will deprive every speedster from their speed, not even things like Thawne are worth it and since it is part of the multiverse it can bring terrible consequences.
- O.O.C. Is Serious Business: Just before she phases out of Flashtime, Killer Frost asks Barry to keep Caitlin safe. Caitlin discusses this with Harry at the end, as she actually remembers her feeling this, unlike every other time Frost has been in control.
- Post-Victory Collapse: After attracting the Speed Force lightning to the bomb, Barry falls tired. After that, he rests while Caitlin and Cisco address the heroics.
- Pun: When Killer Frost enters Flashtime, she remarks how everybody around her is frozen, and this time it's not her fault.
- Rage Breaking Point: After Jay discourages Barry from throwing the bomb to the Speed Force, Barry eventually yells at Jay asking him if he can give the solution.
- Required Secondary Powers: Barry can only bring non-speedsters into Flashtime temporarily before they begin to suffer the negative effects of moving so fast.
- Retired Badass: Jay announces his intention to become one, retiring from active superheroing to train his replacement, an unnamed female speedster on Earth-3.
- The Reveal: The team learns that DeVoe has been active around Central City for at least three years based on the trace of his portals.
- Rogues' Gallery Transplant: Veronica Dale is the villain infamous for killing Green Arrow in the comics, and was never even a character when Barry was alive.
- Russian Reversal: The solution turns out, instead of dumping the bomb into the Speed Force, they just had to bring lightning from the Speed Force to stop it.
- Start X to Stop X: Veronica Dale planned to demonstrate the danger of nuclear technology by using it to destroy Central City.
- Shoo Out the Clowns: This episode is about a dangerous nuclear explosion, so Ralph Dibny is absent again.
- Suicide Attack: Obviously, Veronica fully intends to perish along with everyone else in Central City.
- Time Stands Still: Thanks to the Speed Force, the three Flashes are able to make what should be the instant destruction of Central City stretch out long enough to save the day. Also, Jay is impressed by Barry's new skill at being able to pull non-speedsters into Flashtime.
- Title Drop: Cisco dubs Barry's new ability "Flashtime."
- Together in Death: With her time in Flashtime running out, Jessie chooses not to flee back to Earth-2 like Barry and Harry wanted, but rather to stay by the latter's side.
- Traitor Shot: After Caitlin wishes the mysterious girl luck on her meeting and leaves CC Jitters with Harry, the girl stops smiling and soberly says, "It did". Her previous characterization makes the scene unsettling.
- Travelling at the Speed of Plot: Even without going at full speed, it usually only takes a few seconds for Barry to arrive at the crime scene du jour. Conveniently, however, it takes him about a full minute to arrive, by which point it's too late to stop the detonation.
- What the Hell, Hero?: Jay is not amused when he hears about the plan to take the bomb to the Speed Force.
- Worf Had the Flu: Cisco and Caitlin are unable to solve the bomb issue. This was because Flashtime didn't let them fully launch their techniques.
- Writers Cannot Do Math: Jay mentions that three megatons of energy is equal to about three billion joules. He's about twelve orders of magnitude off.
- You Are Too Late: Barry, Jesse, and the team arrive too late to prevent Veronica Dale from getting in the shipping container. Barry also tries to get the detonator out of Dale's hand, but can't reach it before she detonates the bomb.
