Act 1:
The story begins in Keystone City, where the police is surrounding a bank that is being robbed, as the people inside are being held hostage by the Trickster. After some posturing and grandstanding the Flash arrives, only...the Trickster looks confused and asks who is he, as well as saying he's not the real Flash. Both of them clash, the Flash defeats Trickster (after many fake outs, falls, and just seeing the Trickster use his full arsenal) who is taken by the police, still calling him an impostor and not the real Flash. As the police approach to congratulate him, the Flash runs off, disappearing from site, arriving in an old, hidden home where no one would look for him. There, we see that its set up as a base for the Flash, but not a high tech one, but more like a place where he can quickly change, and research using low tech supplies. It's still somewhat dirty and dusty as well, showing that it's not been that long since the Flash started using it again.
In the safety of his base, the Flash removes his costume, showing a young man, Wally West, who starts reminiscing back to the past. Back when he was Kid Flash and his Uncle Barry was the Original Flash.
With Wally serving as narrator we see Barry as the Icon of Keystone City, Wally gaining his powers, the many different rogues they fought (Captain Cold, Trickster, Mirror Master, Captain Boomerang, Weather Wizard, etc.) as well as their everyday lives and relationships, their training and days they would usually spend together with his Aunt Iris, and the clear hero worship and respect Wally had for Barry, seeing him as his second father in a way.
Yet we also see Wally sees himself as lesser than Barry, and feels that he's holding him back; he's not as fast, not as precise, can't phase through walls, deduce or fight as good as Barry does. Yet Barry always helps hm and keeps his spirits up, telling him how the greatest strength is not science or speed, but heart and empathy.
Then the day everything changed; they'd gotten the alarms about a theft in the Flash Museum, where he and Barry faced against Sam Scudder, the Mirror Master, who's trying to steal the latest showcasing from Mercury Labs (The Multi Array Collider with Giga-Universal Flux For Interdimensional Networks. A machine that should've allowed multiversal travel, but it was never functional, and the research was eventually scrapped) as he feels it can help either upgrade his tech, or just sell it for millions.
They fight, a random security guard gets pulled into it, Scudder's mirror tech interferes with the machine causing it to kill Scudder as the machine begins blowing up. Barry realizes that due to the connection to the Multiverse, and the interaction with the Mirror dimension, the damage that this explosion could cause would be incomprehensible.
The machine is shaking, light is being emitted, sparks are showing as it starts reaching a critical state. Barry does what he does best, he runs. He runs around it fast, moves faster than he's ever done before, pushing his limits till he reaches the speed of light...then goes beyond. Reality warps, molecules and time split. It's not enough as Barry moves even faster as he feels his body breaking down, but he can't stop, he must not stop, even as pain runs through his body he continues until...
He feels it...A calm sensation, something warm and peaceful calling to him...
There's an explosion that pushes everything back, including Wally, who gets up and sees the machine has stopped, its back in its place like nothing had happened at all.
But there's no Barry. Only a charred piece of his costume is left. And Wally is distraught.
Time passed. Barry never came back; the world assumed him dead. Wally and Iris mourned together, Wally tried to be there for her, even as he kept the secret of the Flash since they never had the time to say it. Wally tries to go on as life continues, but he can't forget how it all happened, how Flash is no longer around, and in some way he blames himself for it. One day he goes to one of the old bases Barry used when first beginning, just wanting to be closer to Barry, and finds an old Flash costume there, the first one Barry used when he first started.
Barry had no mentors, no one to catch him when he fell, he did what he did on his own, because in the end it was the right thing to do. All those thoughts ran through his head...and he knew what he had to do.
Back with Wally in the present, wearing the suit, still in the base which he has repurposed so that it's his own, he hears the Police Radio talk about a robbery, and once more goes to fight again.
We then cut to the security guard that was there that night. His name is Evan McCullough, a former scientist from STAR Labs who was fired and could only take this job. Evan was a man with ambition, a man that just wanted to leave his mark in the world, to be acknowledged and remembered, and though he did not get it like he wanted, he figures that at the very least him getting his name on the news would be something.
So, on the day after the break in, he waits for the news, he sees it's being reported by a new reporter named Linda Parks who's speaking about the break in, and Evan is just waiting with baited breath, his one chance to be remembered...and it's missed, as no one even mentions he was there. He saw it all, he was interviewed, but once more he had been forgotten.
And this just enrages him. He breaks things in his apartment, throwing them to the wall, he walks to the bathroom and sees his reflection in the mirror, where with a scream of rage he punches it...and it doesn't break. His arm passes through the mirror as if it was a liquid, Evan looking in shock, then contemplation, and finally wonder as he slowly removes it and looks at his arm, no change whatsoever in it. He tries it once more, and he sees something on the edge of his vision when he does. Turning his head, he sees his arm, but it's coming out of another mirror in the next room. He makes a few more tests before realizing the kind of power he now has.
This changes things. He slowly smiles.
Act 2:
Wally keeps on being the Flash, and tries to take on more of Barry's mannerisms, ways of fighting and acting, just trying to be Barry in general. His family does not seem to take notice, or even care at the moment, just trying to encourage it when they see he's trying to be more like Barry as they see him as a good model, and then going back to their own problems, forgetting he's there. Wally has nearly no one he can depend on, save for perhaps his aunt Iris, but he does not want to burden her, nor reveal Barry's secret. Plus, he also feels guilty for Barry's death as well.
However he's either failing at it or just doing mediocrely as it doesn't feel right. He reads Barry's old notes he took on how to phase through matter, how to run up walls, etc., but he just doesn't seem to get it. Barry was more of a science guy, and he wrote it as such. Wally however was never much for science, and he didn't do that well at school (not bad, just not in the top). He tries his best but it just doesn't seem to be enough. Barry's old suit also doesn't seem to fit him very well, as it's a bit clunky (armored parts which carried on to its later suit) but he tries to power through it.
We also see the perspective of Evan McCullough as he tries to fit in the shoes of Sam Scudder, committing low level crimes and bank robberies while putting himself as the new Mirror Master. With his new available powers he can travel between reflections without the need for the technology, while also moving and controlling mirrors telepathically and creating mirror duplicates of himself. McCullough tries again and again to gain recognition but he's either too low level to be even mentioned, or they take him as a joke. He also trains with his powers hoping to be better at them and move on to bigger things.
Among his actions is trying to contact the other Rogues, who can immediately tell he's not Scudder, and don't take him seriously at all. We see here the difference between him and the Rogues, how some of them have different backgrounds and desires than him, how some are career criminals, some want to be noticed, others just want to hunt the Flash. Evan forms different relationships with them, and even manages to go in a heist or two with some, but in the end he's always the junior, and the one dunked on when everything goes wrong.
Wally also tries to research this new Mirror Master, as he knows Scudder is dead, so who is the guy taking on the mantle? He gets a clue when, during one of the Rogue's heists, Evan's powers malfunction and create a crisis where Wally has to try and save everyone, and while he can't use the same skills as Barry, he still uses what he does know, creatively saving people with his own skills (saving people from a bus by grabbing a wrench and dismantling it fast enough so that no one is harmed). Evan has been nearly unconscious because of the malfunction, so part of his face is uncovered.
Wally recognizes him, and tries to talk with him, but at that moment the news interrupt as they gather near him, ignoring Evan, and enraging him once more as he leaves before he can speak with him.
Evan returns home embarrassed and feeling like a failure, as he can't seem to cut it either as a scientist nor as a supervillain. Where before he thought his powers would help him, now he wishes he'd never been around that...machine...
His mind has a "Eureka" moment as he remembers how the Mercury Labs technology was a multiversal machine, how it supposedly would not work, yet when Scudder used his powers it seemed to work. He's sure he can do the same, and from there he can make sure that everyone, in every part of the Multiverse, will know him and his name.
In order to get a new power source (the Proto Light Optimal Temperature Device) he sneaks into Mercury Labs to steal one, but is stopped by Wally. Mirror Master tells him he's planted bombs all over the city and will blow up at any moment, and Wally runs through the city looking for them. He starts panicking as he can't seem to find them no matter how hard he looks, until he realizes that there never were any. He returns to Mercury Labs to find Mirror Master gone, and the Device stolen.
Wally is beating himself up back in the base, seeing Barry's costume and feeling ashamed; Barry would not have fallen for it, he would have stopped Mirror Master in a cinch, he would've...
That's when he hears the door to his base open, and sees his aunt, Iris West, come in.
Wally is shocked, but iris reveals she'd known about Barry and him being Flash and Kid Flash, and she's always supported both of them. That if anyone is going to live up to Barry's legacy is Wally. That yes, Wally made a mistake, but he's also saved so many lives since he took the mantle. How, despite a misstep, one does not build a legacy in a single step, but slowly over time, just putting one foot in front of the other.
The moment is interrupted by the sound of thunder and lightning. They both go outside and see pulses of lightning surrounding the Flash Museum, with energy waves rippling through the fabric of time and space; Mirror Master has begun his plans. Wally prepares to take his suit, but iris stops him. She tells him that before his death, Barry had prepared something for Wally. She gives him a small box, and opening it Wally finds a
small golden ring.
Act 3:
Outside the museum the press is there reporting on what's going on, lightning all around them, the air blasts strong enough to nearly push them away, when suddenly one of the pulses pushes one of the vehicles into a group of them. That's when there's a bolt of lightning and the Flash blasts through the car wearing a
new modified suit saving their lives before running into the museum.
Inside, Mirror Master has modified the machine with the old tech from Scudder and supercharged it with his own powers. He thinks this is it, he will finally be remembered, everyone will know his name; not as a supervillain, not as a scientist, but as the man who made interdimensional travel a reality. Wally enters the museum and see the machine in the final stages of charging. He tries to speak with mirror master again, warning him of the danger, but he does not listen; this is his legacy, the only way everyone will know he existed, and he won't let anyone get in the way of that.
With a final shout at the end all the glass in the museum shatters, Mirror Master using his powers to levitate them, as well as changing their size and shape, until there are thousands and thousands of mirrors flying and spinning through the museum hall. More are being made every second as they block Wally's path to the machine. He tries to break through, but every shard is a portal into a different mirror and a different part of the hall. He does not know which will lead him to Mirror Master.
So, he tries all of them.
He runs. He moves from mirror to mirror, faster and faster, legs throbbing, lungs burning, going faster than he's ever gone before. he never thought he could either. But there are too many mirrors that he has to go through. Still, Wally runs, fighting the pain, the numbness as it seeps in, as time begins to slow, as he starts feeling something at the back of his mind...
Something calm and warm...
He screams as a blinding white light shines. Finding himself running through the cosmos, feeling panicked before he feels a hand on his shoulder.
It's Barry. Running alongside him. But they're not alone. Looking further he sees someone else running near Barry, and someone alongside that person as well, and on and on...
He looks to the other side and sees the same, so many people running alongside them, all the speedsters that existed or will ever exist, here and in other universes, all in this place where a force guides them, a force that no one can understand, outside of time, physics and logic.
A Speedforce.
Barry guides and comforts Wally through his fear, assuring him they're all with him. To not think, just feel.
On the other side Mirror Master is panicking. The machine is out of control and he can't seem to stop it. He can see now that it will blow up and it will consume the city. He didn't want this, all he wanted was to be known, remembered, but not kill people! He tries using his mirrors to transport the machine, or at least soften the blast, when they suddenly breaks out his control, the machine about to explode when...
Time Stops.
There's a flash of bright light, Wally once more in the museum, lightning all over his body and eyes glowing white. He sees the machine still being blocked by the mirrors; he gets into a running position.
Don't think. Just feel.
And he does that, running not into the mirrors, or avoiding them, btu through the mirrors, vibrating his molecules so fast that he goes through them as if they were not even there. He arrives at Mirror Master's side, still frozen in time near the machine, as it's just a moment away before it explodes, destroying the entire city, perhaps even more. He grabs Mirror Master and takes him away from the machine.
Mirror Master tries to tell Wally they don't have much time; the machine will explode at any moment. but then, the machine just breaks down, all parts just unlocking. Mirror Master is confused, at least until Wally shows him a wrench he's holding. Evan looks down, nearly breaking into tears as he admits his wrongdoings, apologizing to Wally, and accepts that he deserves to go to jail for what he's done.
Wally looks at him, and agrees. But also tells him that he can also do better things outside of it. He tells him he's been researching him, and he can see how he never harmed anyone, how even during the heists to steal money he never took any either, just let the other rogues grab it, or even just returned it back (Flashback of said occasions is shown). There were some close calls, but Wally can see that his intentions weren't malicious. He understands the weight of a legacy, of wanting to make a difference.
So, he makes a deal with him. He'll deal with the reporters and the clean-up, and Evan will give back to the community in any way he can, be it helping people, working at a shelter, doing community work every weekend. And in exchange, they'll be even.
Evan agrees and thanks him, rehabilitating and abandoning his path of villainy. Wally keeps his deal and keeps his name out of it. Wally, now in his new costume, with a newfound confidence and sense of purpose, takes on to the streets once more to protect the city.
Post Credit Scene: Wally is patrolling the city when in a flash of light there's a woman in front of him. Calling herself the
Harbinger, she warns him his universe, and many others, are in danger.
