What does it feel like to look into a mirror and watch the other person blink?

Barry thinks: it's the moment when Zoom comes to a halt in front of him, one clawed hand reaching up to pull back the mask.

Barry's heart stops.

A second Barry stares him down, eyes glowing. A single word passes Zoom's lips. "Surprised?"

His voice is a hybrid: part monster, part charcoal. Almost human.

It's artificial.

Whatever happened to this Barry – this Zoom – destroyed his real voice. No human has a lion's growl – or a lion's eyes.

There's a shard of black lightning between Zoom's palms, eyes a metallic red, cloaked in his suit with a black lightning bolt emblazoned across the chest. Everything about him is powerful. The way he stares Barry down is nuclear; he couldn't tear his eyes away if someone lit the back of his suit on fire.

There is no override command for that sort of authority.

Even if he wasn't transfixed by the black energy pulsing off him, practically playing around his fingertips, Barry would be locked onto that face. Those eyes.

There's an instant where Zoom actually smiles at him, a humorless smirk befitting terror personified.

Then he stabs him in the chest with a claw, and Barry gasps, hunching inward with pain. Pitilessly, Zoom pushes him upright. Barry's right hand reaches for Zoom's; it makes it halfway before Zoom takes it with his left and crushes it.

Gasping for breath, struggling to see anything other than the white noise screaming across his consciousness, Barry tries to stay focused on Zoom's face.

Zoom stares at him, mystified, like he isn't human. Like he belongs to a particularly deadly genera of bacteria. Barry wouldn't call it respect: respect implies certain attributions. But there is definitely something like approval in Zoom's eyes. A lion-like satisfaction at taking down his prey, exertion rewarded with a kill.

He lifts him effortlessly into the air and Barry feels the Speed Force draining from him, a strange sense of duality overtaking him. On one plane he is keenly aware of his own reaction, how yellow lightning surges to meet blue, combative, protective, something-to-fight-for something-to-live-for something-to-die-for, trying to overpower something orders stronger than itself. On that other plane he is aware of the dark impulses, magnitudes louder, loud enough to burn everything he was and turn him into pure, raw energy. Insatiable. Hungry.

The Speed Force is breathtakingly huge, but Zoom's presence is a void so strong it hurts, like it'll never be enough, like he's colder than space and time itself and only the lightning keeps him alive. It's static electricity across his skin, sensation if not heat, reality if not comfort. He can feel the speed, can feel the way air tastes and smells and sounds, is aware of everything, every future, every past, but none of it seems entirely real, as if life and death aren't really apart, are both condemnations.

Looking into Zoom's eyes, Barry sees one future: a world with only one Barry.

He can feel Zoom's fear, a force so potent it makes breathing hard, because if Zoom dies than the cold will only get stronger.

There's an out-of-body moment when neither Barry exists completely, their identities indefinably mixed, and it's in that moment Barry takes Zoom's hand and makes him let go.

Zoom's hand goes lax.

Barry drops out of his grip, the world slowing down to stillness as a surge of adrenaline plunges him into the heart of the Speed Force.

Barry stares at Zoom, frozen in time, and he can see Zoom looming triumphantly over his broken body. He shifts his gaze and sees himself putting Zoom away, banishing him to his own hell, and he thinks it won't kill you because the Speed Force doesn't create or destroy. It reclaims, restores, reinvents. But it does not destroy.

The lightning around him is warm and powerful, heady. There is no pain and his body is whole and powerful and his own, adopting a gladiator's stance as he waits for the beast to make its own move. Zoom has his mask on, ready for the fight.

There is the tiniest twitch in Zoom's hand and Barry watches the blue lightning bolt crash into the wall – crash into him –

Return fire.

He doesn't hesitate, moving forward, not at a run but in motion, grabbing it in mid-air as it surges from nothingness to meet him and launching it back at its maker.

Zoom crashes into a wall, red eyes dimming, and Barry feels the resistance, but Zoom is cold, hollow, a husk, and he doesn't harness the energy, it controls him.

It takes Barry by surprise when he sees Zoom attempt the same trick, but he dodges when he sees that it's a trap, the second, white lightning bolt frying a hole through the wall where he would have been standing. It helps to be able to see himself being vaporized, being mortally wounded, and being able to emerge unharmed in the femtosecond before impact.

Zoom is angry now, fucking angry, and Barry can feel the emotion like his own and it blocks his vision momentarily, making him vulnerable to the way Zoom knocks him to the floor, pinning him with enough force to break orbit, and shoves a hand through his chest.

Barry sees himself turning transparent, vibrating fast enough that Zoom's hand passes harmlessly through his chest, and it happens because he doesn't have time for options two or three. It's an RPG game, he thinks grimly. Just choose the right door. You've got all the cards.

Then he gets his first critical message. He sees himself abruptly losing strength and dying, Zoom putting on a surge of speed and overpowering him, and Barry being unable to maintain the transparency and getting his heart crushed.

There's only two femtoseconds to decide.

(It should take thirty one thousand years to count to one trillion I can do it in three seconds—).

Then he does the only thing he can: he launches a counterattack.

Zoom deflects him, casually turning transparent himself when Barry claws a hand through his chest, but he's exerting himself just as hard as Barry and someone is going to break, and Barry can't see who because all he can focus on is keeping himself as insubstantial as possible.

Then the world shakes, and it isn't much but Barry feels a fierce sense of joy because God, you are so late before a boulder the size of his head smashes into Zoom's back, breaking his concentration.

Barry sees himself killing Zoom – only to have Zoom return the favor (game over). Using his ten billion second lead wisely, he elects instead to shove him back, putting as much distant between them as possible, and it's good that the suit can't even register his speeds or he'd fry all of the internal mechanisms with how quickly he darts to the opposite side of the room.

He's already slowing down, settling into nanoseconds so he can follow Zoom's attacks in real time.

Losing the ability to anticipate his moves means he catches Zoom's punches to the jaw-gut-leg with a grunt, but he's fought with Oliver enough to know hand-to-hand combat, has had his ass handed to him so many times that he finally knows a thing or two. It's not about power: it's about physics. Case in point: Thea can flip him despite weighing three-quarters of his size, and Barry uses the same principle of lean-deflect-bend-launch to escape Zoom's assault, staying on the defensive.

He knows without asking that Zoom can't be knocked out. Zoom doesn't eat or sleep or even breathe like normal humans do: he's energy, pure, raw energy, and defeating him has to be permanent or not at all. Anything less? He'll reform. He'll come back like a bat out of hell and destroy Barry when he thinks he's safe.

Permanent or not at all, Barry thinks, spinning in a slow circle to avoid the lightning bolt that singes his suit in passing before crashing into the wall.

He can only see two scenarios at this speed, but he gets lucky when his gaze falls on the floor. When he thinks, gravity.

It's the weakest of the four forces. Were it perceptibly huge, like the proton, Zoom could crush it.

But Barry sees it. Terminal velocity. Taking Zoom down on a level where he's powerless. Force him into the city, into open air.

Plan in place, Barry listens for the tell-tale ceasefire as more of the wall crumbles around them. Cisco's really kicking up a storm, Barry thinks; they must have Jesse and Patty already or they couldn't risk tearing the building down on top of them.

Then his scenario vanishes as the power goes out and he can see the wave of pitch-blackness spreading across the room and Barry thinks in the last nanosecond before he loses sight of Zoom, This is gonna be fun.

And then it's just them and their lightning.

Barry closes his eyes for a second, forcing his body to acclimate, to ignore the loss of one of his primary senses to focus on the shifting heat in the air.

It's like detecting a black hole: you don't look for the light it emits, or the shadow it casts across a sun.

You look for the absence. The void.

Barry senses it and ducks as blue lightning crackles overhead. Zoom is blind here, too, and Barry's throwing off heat, his own star broadcasting into their own private universe, but he's too bright, making his position hard to define. The blue lightning misses by a wider margin, shattering against the wall.

More boulders are coming down and Barry thinks, I have to get out of here. Zoom doesn't seem to share his concern as he launches another blue bolt. Barry wonders if this is just what happens when you become Zoom, where even the notion of being crushed doesn't scare you because you know you will survive, you will force yourself to crawl back to life if you must. You will not go quietly. You will not go quietly.

That's the moment when the ceiling comes down and Barry has time to see three scenarios: phasing through a wall, and Zoom is gone and he has no idea if he'll ever get a chance like this again, if he'll be able to do this again; rocks overhead crushing both of them, and Barry's strong but he isn't that strong, he's not like Zoom, an intransigent force in the universe, unconfined to its laws, he dies under the rubble; and then—

Then he makes his choice.

Barry has one shot: and he takes it, sprinting straight for Zoom, feeling the energy light a tidal wave around him, and Zoom glows with his own energy as the lightning bolt departs from his outstretched arm but it shatters against Barry's as he pushes Zoom up against a wall.

And then he becomes Zoom.

. o .

He's Barry Allen, jogging to work with one hand on his satchel because he's late, again.

Pushing open the doors to CCPN, he steps inside the isolated world that is his workplace. Not many people talk to him; those that do, snap. There's a tension to his smile when he responds to the people who barks orders at him, the people he has to be nice to if he wants to get anywhere. Who laugh at him for chasing impossible dreams but I saw him, I saw the man in the yellow, he killed my mom.

He smiles through it, produces brilliant articles. According to virtually everyone around him, he's just another aspiring journalist with little promise, but he vows, he swears, he promises that he'll make his mark on the world. Watch him.

But then he becomes the man who unobtrusively and virtually unmourned disappeared four years ago, who was never seen or heard from again. Presumed dead.

There are days when he wishes he had died.

Instead he was secretly, unlawfully experimented upon because he was flagged for having the wrong kind of blood, blood with potential, after a routine lab test. They found something exciting and got something so much more when they discovered that his cells regenerated. Thankless people wanted his abilities, would do anything to get them, and they broke him on that crucible until there was nothing left of the aspiring journalist from four years ago.

Then there was an explosion, such an untimely, unavoidable explosion (as they tell the reporters over and over and over until Barry wants to beat those words from their collective consciousness because it wasn't an accident) that changed his life forever. That galvanized the cells in his body and gave him access to the one thing he never knew he needed: speed.

Barry Allen thought he could be safe. He was unleashed him from their grip forever, made fast enough no one could ever catch him, and he thought he would be okay. But he wasn't safe, there were others like him, powerful others, and his first attempt to destroy the First Other (the speedster I call Reverse-Flash, the man who killed our mother) failed.

And those people, those people who thought they owned him, tried to take him again when he failed, when he was too weak to fight them, too stricken by grief to resist them. They captured him, tried to subdue him, but he had lightning now, he had strength that they'd never dreamed of, and he broke his shackles. His rage was so unconsumable he burned the entire fucking military base to the ground.

Then it becomes like life itself as he discovers just how fast and strong he is, how he doesn't have to break under the law's punishing hand anymore, how he doesn't have to submit to them, how HEROES DIE, every day, like Joe in that fire, like his dad in prison, his mother at the First Other's hands, how people he loves and cares about will be taken from him and those he admires will be corrupted and everything in the world is just going to burn.

But he can stop it. He can take the bullets from their guns. Put out fires. Save people. At first, it's rewarding, but they've still got a price on his head and they will never give up. He has to destroy them.

One at a time, he does. Takes out every person who ever hurt him. Who hurt other people. Soon it's less killing and more reshaping, turning the world into a place where people like him never have to suffer at the hands of other people.

He gets faster and stronger and faster and better and faster and more invincible every day. Discovers that when he runs, he can just keep running, he doesn't actually have to stop, his body can take it, his body can take anything, and he feels himself reaching a threshold where he should stop, should break away from the addiction before it destroys him, but it's not his choice anymore.

That Last Good Day, he drinks coffee, lies on a soft bed, listens to the crickets at night, and is pain-free for eight glorious hours.

Then he goes for a run and never comes back.

The energy makes him – POWERFUL – immune to love, to disease and feeling and passion – and cold. At first, he notices it because coming down from the edge feels like submersing himself in cold water. The ringing in his head is intolerably, his voice box is shot, everything about his body is pain. It's easier and sweeter and better to run, so he does.

He keeps running, and running, and running.

And somewhere he loses that other person, that person who craved coffee and hugs and grass. He loses what it means to feel sorrow or joy, protected at all times from his own emotions. He loses what it feels like to sleep or eat or stop, exists to run, to prove to the universe that he is strong. He lives to earn the energy's trust and affection and worthiness because it's the only thing that matters.

It's the only thing that matters.

And somewhere along the way, he stops feeling at all.

He stops feeling.

He stops feeling.

The lightning burns, the energy pulses, but none of it has substantiality. Everything is numb. Chafing his hands together, running them through his hair, he can't feel anything. Just the cold. The cold that will not flinch in the face of fire, that will not relent in the midst of an endless assault, trying, trying, trying, always trying to get warm, please, please, please.

. o .

Zoom shoves him back so hard Barry feels his skull crack against the base of the wall, splintering him back to reality, and there's an undefinable emotion on Zoom's face, flatness, but tears stream down his face as he presses Barry harder, and harder, and harder against the wall, choking him like the energy that choked him, like the love that wasn't love, the love that was pain, that destroyed him—

"Like I'm going to destroy you," Zoom growls, subsonic, in the microsecond before an explosion shatters their field of vision.

Barry sinks to the ground as Zoom does, mortally wounded, a plasma wound carved into his back, and he's shivering hard, breathing so hard Barry can almost see the clouds of fog, the please, please, please, I'm so cold.

"Hey," Barry says, doesn't know what to say, when Zoom tries to stab a hand through his chest and Barry catches it effortlessly instead. It doesn't even look like him anymore, a stranger with his face. A stranger. A stranger.

But still a human, somewhere, burned out but still a human, somewhere, and Barry does the only thing he can think of.

"It's okay," he says, placing a hand over the gaping wound in Zoom's chest, feeling the dark energy retreating slowly. "It's okay."

He can feel tears, can't tell what they're for – whether they're his own or Zoom's doesn't seem to matter, they are one – and he repeats, "It's okay."

Zoom tries to kill him, but Barry deflects easily. He's aware of the Reverse Flash approaching, a plasma gun in hand, a bitter, triumphant look on his face, and Barry thinks, He's a hero in this lifetime.

He killed you to save them.

You had to be destroyed.

"I'm sorry," he says softly as Zoom's eyes go dark, his hand still gripping Barry's wrist with enough force to break but he doesn't care. Let him hold on. Let the drowning have that comfort.

"I'm sorry for what they did to you. And I'm sorry –" a hard swallow because he never meant to hurt anyone, he just wanted to stop hurting.

"I'm sorry," he finishes, flat-lining, feeling a surge of emotionality because he can feel Zoom's mind like his own. Can feel that grief, that fear.

The last thing Zoom does before he dies is pull off the mask and say in that same halfway voice, animal, human, creation: "Sorry changes nothing."

And then, as Barry's own vision fades, away of two sets of hands, warm, familiar, pulling him upright, away from the corpse cooling in his hands, he thinks with his last gasp of consciousness, It didn't have to end this way.

. o .

When Barry wakes up to the feel of soft sheets and a familiar soreness in his body, he knows, It's over.

Opening his eyes takes effort, but he makes it, looking between Caitlin and Cisco.

"Hey."

They grin, Cisco sitting on the edge of the bed and clasping a hand over his knee. "Hey," he echoes companionably.

"How are you feeling?" Caitlin prompts.

Barry makes a soft noise. Inventories. Not as bad as he thought. Not as good as he would hope, but he's had worse. With a rueful smile, he says, "Whole." Then, sitting up slowly and unstrapping himself from the heart rate monitor, he asks, "The others?"

"Safe and sound. A few abrasions, but nothing that shouldn't heal quickly."

"Patty's a badass," Cisco says, very seriously. "She took out the power before I even got in there."

Barry smiles a little.

"When the roof came down . . ." Caitlin exhales.

"I was worried, too," Barry admits. "I took a risk. It paid off."

"Pretty sure 'traveling to an alternate dimension to save your girlfriend' counts as one hell of a risk," Cisco admits. "Unless you're Batman, in which case it's probably just another Tuesday."

Barry huffs softly, feels a residual ache in his chest. Watching Caitlin unhook him from the IV, he waits until she's done before standing and stretching his arms over his head. "Ohhh," he says. "It feels good to stand up again."

"It'll feel even better to do it on home turf," Cisco adds, clapping him gently on the shoulder and passing him a Star Labs t-shirt. "Jay said you could wear his sweatshirt."

Barry unsuccessfully suppresses a smile. "Did he?" Tugging it over his head, he grabs a fistful of the soft fabric, thinking back to the day when he woke up from a nine month coma. "I love this shirt. Tell him thank you."

"Tell him yourself," Jay says, entering the room. "Hey, Barry."

"Hey, Jay."

Jay looks him over, asking shortly, "You okay?"

Barry thinks about it for half a second, nodding slowly. "Yeah." Then, unexpectedly giddy at the thought, he finishes, "I'm okay."

"Good." Looking over his shoulder, Jay adds, "There's someone who wants to see you, if you're feeling up to it."

Nodding, Barry accepts the half-hug Cisco gives him before venturing out of the side room and into the main lab.

Patty has her back to him, watching a news feed with an unmistakable smile. ZOOM DEFEATED, the scroll proclaims. FLASH RETURNS TO CENTRAL CITY.

Watching the feed, Barry waits a moment in silence, taking in the new reality, the undeniable beam to the reporter's face, before saying simply, "Hey."

Patty turns sharply to face him, closing the distance between them and hugging him hard.

"It's okay," he tells her, feeling a strange echo of you've got to keep them safe now, this is your job now overtaking him.

He doesn't always do it right, and he couldn't do it without them, but there are things only he is capable of.

For better or worse.

"We're going home."

. o .

What is home?

Home is FLASH BACK – DOUSES FIRE, SAVES THIRTY.

Home is Joe hugging him hard, telling him you scared the hell out of us, taking them out for drinks because to hell with it, they need to celebrate.

Home is the way Iris hugs him tightly until he can finally breathe again and believe that it's real.

Home is a lot of things – Big Belly Burger, lab reports, meta-humans, the Arrow team, fresh air, fresh coffee, fresh sheets – but above all else, home is the way he feels when he runs. Home is the way he feels when he sets a five-year-old on the pavement outside a burning building, embracing him for fully six seconds before returning to Star Labs. Home is the way he feels when the cops brag about their latest catches, corrected by their coworkers for the Flash's inevitable influence, and the secretive grin he shares with Joe.

Home is waking up to a world where he gets to be a hero. Home is waking up to a world where he gets to run and feel more alive for it.

He generates the Speed Force and it's a good thing.

It can be warped. It can be turned into terrible things.

But it's also the reason he is The Flash. And the Flash is a hero.

The Flash is someone Barry can be proud of, someone he can aspire to be like. To earn it. To become it.

To be the hero Central City deserves.

To be the person he wants to be.

And he knows that it extends beyond, Save them.

It's remember him.

Don't let it break you.

Remember what matters. What you care about.

What will keep you going when you want to stop.

What will make it worth it.

What makes it worth it, Barry knows, is the way Cisco douses a lab fire with a fire extinguisher while Caitlin admonishes him loudly about messing with flammable chemicals in the lab, Cisco and Cisco snarks back at her.

Just getting to wake up and be a part of their life – their life, because all of them were struck by that lightning – is worth everything.