"To understand what I'm about to tell you, you need to do something first. You need to believe in the impossible. Can you do that? Good! See that red blur? That's me. My name is Barry Allen, and I'm the fastest man alive."Barry Allen, a young forensic investigator in Central City, is struck by lightning caused by a Freak Lab Accident at the S.T.A.R. Labs Particle Accelerator and doused in chemicals from a different Freak Lab Accident at the same time. Waking up from a coma nine months later, Barry discovers he now has the ability to move at superhuman speeds. He resolves to use his power for good, but the Particle Accelerator accident has created other "metahumans" who may not share his morals.
—Barry's opening monologue.
- Anger Born of Worry: The reason Barry is so angry that the trio at STAR labs lied about other people not being affected by the accelerator's explosion is because he's concerned about the people of the city being in danger.
- Arbitrary Skepticism: Lampshaded when Wells is telling Barry about the antimatter, dark energy, X elements, etc. that fell into our world due to the accident.Barry: Those are all theoretical.
Wells: And how theoretical are you?
- Arc Words: Being the pilot, the series' major Arc Words, "The Impossible", "Run, Barry, run!" and "Centuries", were mentioned.
- Artistic License Law: In the time it took Barry to run back home (an hour or so after the murder at most) the police were already taking Henry to jail obviously having not even bothered to check the area giving a feel for how little investigation must have been done.
- Bad Future: It seems that at some point in the future, Flash will disappear (possibly die) battling a mysterious force powerful enough to turn the skies red. Dr. Wells is either from this future or somehow knows about it and seems to be manipulating Barry to bring it about.
- Belligerent Sexual Tension: Iris starts out not liking Det. Thawne for being too proud of catching a purse snatcher, before segueing into agreeing with her father's description of him as "Detective Pretty Boy".Barry: Detective Pretty Boy?
Iris: That's what dad calls him. ... He is pretty, though.
- "Run, Barry, run!", both from Henry Allen the night his wife is killed, and later at the end of Wells' speech encouraging Barry to beat Mardon.
- At the beginning and at the end, Henry and Barry talk about a fight involving Barry.
- Brutal Honesty: Joe bluntly tells Barry to move on with his life by bluntly telling him what he thinks had happened during the night Nora Allen was murdered.
- Bullet Time: The series uses this for the audience to get a feel for Barry's speed and perception of the world.
- Call-Back: The Arrow advises Barry to take his own advice and wear a mask; Barry had previously advised Oliver on the matter in "Three Ghosts".
- The Chosen One: Oliver tells Barry that his powers chose him.
- Comic-Book Movies Don't Use Codenames: Averted for the Flash but applied to Mardon (although this is Clyde, not his brother Mark, the actual Weather Wizard); in-universe, this is because Cisco hasn't picked up his habit of nicknaming metahumans yet.
- Continuity Cameo: Just to remind the audience that this is an Arrow Spin-Off, Oliver Queen, the titular character of that show, makes an appearance.
- Differently Powered Individual: Harrison Wells calls people with powers Metahumans, and becomes the widely-accepted term.
- Do Wrong, Right: After scolding Barry for getting into a fight, Henry asks him if he won.
- Early Installment Weirdness: So far, the only episode to actually show a Sherlock Scan from Barry on-screen. On the audio commentary on the first season DVD, the producers say they intended to do more but found it too distracting for viewers.
- Establishing Character Moment: Young Barry is shown running from some bullies and getting beat up. A later shot shows him telling his mother how the bullies were picking on kids, fully establishing Barry as someone with a good heart who stands up for people.
- Fingore: While showing off his speed to STAR Labs, Barry flashes back to the memory of his mother's murder, and then crashes. Back in the lab, Caitlyn gives him an X-ray scan of his bones on one of his hands until his Healing Factor kicked in.
- First-Episode Twist: Harrison Wells can walk and is from the future.
- Foreshadowing: Whilst Harrison Wells is showing Barry around S.T.A.R. Labs, they walk past an animal's cage which has clearly been broken out of, with a sign reading "Grodd".
- Freak Lab Accident: How the Flash gets his powers. In a twist on the comics, the freak accident in his lab (lightning + chemicals) is directly caused by another freak accident at S.T.A.R. Labs (particle accelerator-induced explosion + storm).
- Freeze-Frame Bonus:
- In the Wham Shot, an article about a Wayne Tech/Queen Inc merger can be seen on the newspaper from 2024.
- In Barry and Mardon's first confrontation, a wisp of fog is seen exiting the shattered passenger-side window before it flips over and crashes. A blink-and-you'll-miss it, as it's meant to explain how Mardon escaped the car before it got totalled (with Barry having to climb out of the shattered windshield).
- In the "ball of lightning with a man inside it" at the beginning, you can see both red and gold lightning from Speed Force. The lightning that carried Barry away was just gold. There were two speedsters in that lightning, and young Barry was carried away by, if not Barry, then another speedster in red.
- The Glomp: Iris literally leaps into a hug with Barry when she first sees him awake from his coma.
- A God Am I: Clyde Mardon starts getting a God complex after gaining his powers.
- Healing Factor: Barry heals from a fracture in three hours.
- How Do I Shot Web?: Barry spends some time realizing something strange is going on with him in an alley behind the police station, which involves him crashing into a police car hard enough to shatter the rear window.
- How We Got Here: The episode opens with Barry is running through the city, explains he's the fastest man alive then flashback shows how he got his powers. He's actually telling the story to the Arrow.
- Ice Queen: Caitlin — she's a Perpetual Frowner and generally aloof and distant. And her last name is Snow. To top it off, her comic-book counterpart— and eventual alter-ego in the series— is the supervillain Killer Frost.
- The Knights Who Say "Squee!": Barry is a huge fan of Dr Wells, and is extremely excited when he gets to meet his hero.
- Like Brother and Sister: Iris apparently feels this way with Barry. The latter feels differently.
- Mass Super-Empowering Event: The particle accelerator explosion gives people throughout the city, possibly all over the world, powers.
- Mistaken for Murderer: Barry's father was accused of killing his mother.
- Mythology Gag:
- Iris describes the Particle Accelerator as an "Atom Smasher".
- The S.T.A.R. Labs crew tests Barry's Super Speed in an abandoned Ferris Air airport.
- The 2024 newspaper shows Barry wearing the classic Flash suit, as well as a crisis involving the sky turning red.
- Just like in the comics, Barry first discovers his powers when he perceives a falling tray of food in Bullet Time.
- Mundane Utility: Oliver muses that Barry wouldn't have "run 600 miles" all the way to another city just to visit him.
- Nice Job Breaking It, Hero!: Despite his God complex, Clyde Mardon is perfectly happy using his powers to rob banks until Detective West's sarcastic comment about why a God would need to rob banks prompts him to think bigger.
- Not So Above It All: Barry says, "Cool!" after seeing Oliver Queen dramatically swing away to another building. Then Oliver has the same reaction to seeing Barry shoot away at super speed.
- Oh, Crap!: Barry walks back into S.T.A.R. labs, furious that he wasn't the only one affected by the ring's explosion. Wells exchanges a look with his team...
- Parental Abandonment: Barry's mother was murdered when he was a child and his father was arrested for the murder.
- Perpetual Frowner: Caitlin apparently never smiled for nine months after the S.T.A.R. Labs accident, which cost her her career and killed her fiancé — Barry successfully saving the city from Mardon's tornado changes that (the not smiling, that is).
- Retcon: The Arrow episode "Three Ghosts" depicted Barry's lab accident happening on the night he returned from Starling City, and showed Barry to be on the phone to Felicity Smoak immediately before it, with Barry telling her that he missed the cut-off in the line at S.T.A.R. Labs. The Pilot instead depicts Barry as being back in Central City the morning before the accident, removes the phone call, and has Barry and Iris at S.T.A.R. Labs before leaving to file a police report after Iris is robbed, with Barry heading to his lab from there.
- Rule of Cool: Why is the Flash insignia a lightning bolt? According to Cisco Ramon, it's so it's "not boring".
- Rule of Symbolism: Barry wakes up 9 months after he went into his lightning-coma. He was reborn as the Flash.
- Science Hero: The Star Labs team as Barry's support, with Cisco covering the tech, Caitlin the medicine and Dr Wells the everything else. Barry himself, of course, has the superpowers.
- Sherlock Scan: Barry does this at the crime scene near the start of the episode, determining the year and make of the bank robbers' car by simply looking at the treads left behind on a small patch of dirt on the sidewalk, complete with Sherlock-style onscreen overlaid graphics describing exactly what his Sherlock Scan is revealing to him with graphs and measurements.
- Shirtless Scene: While recovering from the lightning impact, Barry is obviously shirtless so his status can be known better. When he recovers, he can contemplate how he became slightly muscular after being impacted by the lightning.Barry: Lightning gave me abs?
- Shout-Out: The opening scenes of the episode and the entire series (shot from the sky panning down to the city while The Hero is narrating on how) is very similar to Kick-Ass.
- Spinoff Sendoff: Barry visits Oliver to talk about his new situation and Oliver tells him that his powers chose him and that he could be a better vigilante than him.
- Super Speed: As of first waking from his coma, Barry clocks in at around 700 mph, just under the sound barrier.
- Throwing Off the Disability: At the end, Wells enters a secret room and rises from his wheelchair, showing that he has merely been feigning his injury, to top it off, he also shows that he apparently doesn't need his glasses either.
- Time Skip: Barry woke up after 9 months since he was hit by lightning.
- Tornado Move: Clyde Mardon pulls one off when he starts thinking big.
- Touching Through Glass: Barry and his father do this when they talk to each other.
- Tragic Keepsake: Barry borrows a pen from a guy to sample fecal excrement. The guy informs him that the pen was given by his father before he died.
- Wham Shot: The episode ends on the reveal that Harrison Wells is not actually crippled, is from the future, and that in 2024 the Flash is set to vanish in the midst of a crisis involving the sky turning red.
"My name is Barry Allen, and I am the fastest man alive. A friend recently gave me the idea for a new name... And something tells me, it's gonna catch on!"
— Barry's closing