Authors Note:
Written for Snowbarry Spot's April Minibang, using the theme of Entropy - 'lack of order or predictability; gradual decline into disorder'
This is an idea I've had saved away since S6 premiered and I'm so happy to have finally gotten it written (and to close out all the tabs I had open on chaos theory and blackholes lmao). Please let me know what you think!
I.
Entropy. Chaos. Disorder.
It is the natural order of the universe, or so they say.
But as a scientist, though it is far from her field of expertise, Caitlin knows that there is order to be found in chaos. That even in complex systems full of unpredictability and uncertainty, there are deterministic variables that make up orderly patterns and behaviors.
Logically, Caitlin knows this. But as she clings to the pole for dear life, arms straining against the gravitational pull of the black hole that lies just beyond Jitters' doors, logic flies out the window.
No one knows what lies beyond the event horizon of a black hole.
At least, no one knew until Caitlin Snow got sucked into one.
II.
In what should be the final moments of Caitlin Snow's life, everything happens so quickly that later, she can only remember the details in fragments.
She remembers the chill of her hands and the weight of the ceramic mug in her grip, she remembers the sweet taste of coffee on her tongue and the almond croissant she'd picked apart and half-eaten.
She remembers getting up to grab a napkin and then -
The rattling of glasses in their plastic tub. The banisters upstairs shaking and thrumming with deep vibrations. The light that suddenly dims.
She remembers the glass from the front door exploding into the shop, thousands of tiny shards racing towards her and then suddenly, flying back in reverse. There was the wind howling in her ears and the chilling, clamoring screams of the other patrons.
Caitlin could remember the futility of her scrabbling for purchase, fingers slipping against the floor and the sleek side of the counter. Seeking for a foothold, a ledge that didn't exist.
It's by sheer luck that she'd managed to grab onto the pole, her arms straining against the pressure that seeks to suck her into a pitch black void. She remembered screaming for Frost, wanting to freeze her hands onto the pole – a truly terrible idea, in hindsight – but there was nothing.
The last thing Caitlin remembers before she's sucked into nothingness is a blur of red and yellow, a gloved hand reaching for hers.
III.
Barry sits. Unmoving. Unblinking. Silent.
"Barr."
He blinks and he can hear Caitlin screaming.
"Barry, baby, please, you have to eat something."
He blinks again and sees brown eyes wide with fear, caramel brown hair whipping around a pale face, a yawning void open just beyond.
"Barry, man, you can't blame yourself."
He blinks again and he's not fast enough, he's not fast enough –
She slips through his fingers and falls into an ominous pitch black void that closes behind her, leaving no traces of the woman he'd failed, only silence and destruction in its wake.
Bile rises in his throat and finally, Barry moves.
Around him, the lab is dark and silent, the others having retired to the lounge after failing to get him to respond. He destroys everything in his vicinity, sweeping beakers and test tubes off the counter. They shatter at his feet, bringing no respite to the nebulous emotions that threaten to tear him apart from the inside.
But there is no meaning to be found in destruction.
Chaos has never felt so futile.
IV.
At first, there was pain.
Excruciating, agonizing pain that made Caitlin want to scream except she found there was no air in her lungs. Fire raced along her veins as her very cells twisted and threatened to break apart, agony rooting itself into every fiber of her being.
There's a roaring in her ear, a sharp contrast to the deafening silence that surrounds her.
She tries to scream and chokes on nothingness. Everything hurts.
She feels her eyelids close and then, there is –
Silence. Darkness.
Caitlin wakes to a vacuum.
She jerks awake with a gasp and is horrified to note her chest doesn't heave with it.
The air around is cold, sharp but there's stillness to it and try as she might, Caitlin can't seem to inhale or expel any of it. Alarmed, she takes note of the rest of her body, methodically going over each body part, checking her body's reactions.
Satisfied with her findings, she stands, inspecting her surroundings. She finds oblivion to be dark, oppressive and lonely.
As a child, she used to be afraid of the dark. Prone to a hyperactive imagination, she'd imagined people where there were only coats on a coat rack, monsters scratching at her window when there were only branches tapping against the glass of her window.
She could remember laying in her bed late at night, scared to fall asleep, unnerved by the silence of the house and the darkness of her room. She knew though that if she only turned on the light, everything would be in its place.
Now, the nothingness that surrounds her is so absolute, so deafening in its absence of everything – it strikes a fear ancient and primordial.
In the absence of everything that is, she screams. She screams until her voice is hoarse and her throat feels rubbed raw, calling and calling into a void that doesn't answer back.
Her voice doesn't even echo.
V.
It doesn't take them long to make the connection to Chester.
But without Caitlin, they almost don't make the connection between Chester's consciousness and the black hole itself.
"So, how do we get them both out?"
Silence.
Then, hesitantly, quietly, as if it pains him to say it, Cisco replies: "Barry, we don't know that Caitlin's still…"
He trails off, eyes wet as he blinks and looks away.
"She is. She has to be." Barry's voice is thick with emotion, firm despite the desperation. He had to believe that, if only for his own sanity. He couldn't lose anyone else, especially not Caitlin. Never her.
At his side, Iris is silent and Barry can't stand the pity in Cecile's eyes.
His next words are quieter, softer but just as firm and soaked in devastation. "I'm not losing anyone else."
He had failed to save Caitlin once. He wouldn't fail her again.
VI.
Caitlin walks.
She walks for so long, her legs should ache with the strain of it. On average, there are about 2,500 steps for every mile and Caitlin has counted five. But time has no meaning in this void and though she marches through the darkness, an arrow set on a straight and narrow course, there's a dizziness that increases with every step.
She begins to suspect whatever plane she walks on may not even follow the laws of physics. .
As she walks, she tries to dredge up everything she could remember about black holes. Over the years, she'd watched a lot of documentaries with Cisco and Barry, ranging from medical mysteries to emerging mechanical engineering technology to real crime documentaries.
But with so many bizarre encounters over the years, they'd watched more than their fair share of documentaries on space and humanity's evolving understanding of the universe. As it was, science could only speculate what lay beyond the horizon of a black hole but every bit of information mattered if Caitlin was going to make it home…
If if if….
The word seems to taunt her and if Caitlin could panic, she would. Did the lack of air in her lungs mean she was dead? Or was the act of breathing simply unnecessary in this vacuum she'd awoken to? Did her friends think she was dead? Had they given up on her?
She'd known them long to know with certainty that Barry was probably beating himself up at this moment, Cisco quiet with grief. But for a team that had beat the impossible time and time again, was this the final line in the sand?
Feeling hot tears well in her eyes, her body heavy with the helplessness of her situation, Caitlin blinks rapidly. Then, she blinks again.
In the distance, so miniscule the speck may as well be non-existent if not for the fact that it's so blatantly stark and different from the endless darkness that surrounds it, she spies a glimmer of something.
Breath catching in her throat, Caitlin stumbles towards it, breaking into a run as the speck grows closer.
A blue crystal, almost as tall as her and as thick as the trunk of a tree, juts from the darkness. It hums with energy, pulsing a soft blue that seems to beckon her closer with every gentle pulsation.
Suddenly afraid, Caitlin hesitates.
For an endless moment, the choice hangs before Caitlin, the unknown giving way to more unknown. Then, like a rubber band snapping back, the decision comes to her with starting clarity.
With a shaking hand, she approaches the crystal, gasping as her fingertips find its smooth cool surface. Almost as if in response to her touch, the crystal's vibrations intensify, the humming reminding Caitlin of an angry swarm of bees.
Caitlin's attention seizes on the surface of the crystal, where a murky image is sharpening and coming into focus. Her heart seizes in her chest as the realization strikes like a lightning bolt down her spine.
She watches, in horror and awe, as those final moments in Jitters play out across the crystal's surface. But it's not a memory. Caitlin knows that much –
She knows because, this time, Barry saves her.
VII.
It takes Caitlin ages to figure out, the answer teased out in stuttering, halting progress.
But she thinks of Cisco and a cluster of crystals appear in the distance.
She thinks of her mother and sees a universe wherein she has a brother, Carla's face different yet familiar as she presents the bundle from her hospital bed, a young Caitlin peering down at the baby's face.
She thinks of Ronnie and a field of crystals rise from nothingness. They sparsely line the "floor", the air above her head, the space at her sides. She sees worlds not unlike Earth-2 or Earth-X, where Ronnie and her exist on the wrong side of the law.
Deeper and deeper, she goes, following the crystals like a trail of breadcrumbs. She sees alternate timelines and lives where Ronnie seemingly lives and they have a future together, welcoming kids into the world in some, fighting side by side in others.
She sees Iris and Joe and Cecile, people she doesn't know too. A younger girl with dark hair and hands that flare with ultraviolet light. A young Black man with glasses and a face that's always open and smiling, lit up in excitement.
Their crystals are fewer in numbers but like a series of snapshots, they paint a larger picture.
Phase space, Caitlin thinks suddenly.
Like puzzle pieces falling into place, the fundamentals of Chaos Theory come to the forefront of Caitlin's mind – after all, what embodies the essence of chaos more than a black hole?
There was nothing quite as daunting and unpredictable in the universe.
Though the applications of the theory ranged from mathematics to computer science to meteorology and ecology, she knew there were commonalities in chaotic systems and phase spaces were essential to predicting the unpredictable.
Brows furrowing, she frowns as another aspect comes to mind, the details hazy as she pulls them from the recesses of her mind. But like water slipping through the cracks, the thought escapes her.
It taunts her, just out of reach as she examines the crystals around her. She pauses, catching sight of Barry on the surface of a pale purple crystal.
Caitlin blinks and suddenly, where there was once pockets of nothingness, there are crystals filling in the gaps. Their soft light fills the space around her, cold surfaces colorful and alluring as they line the path forward. It feels at once oppressive and daunting, a far cry from the darkness of before.
As she stares down the path, she can't help but wonder just what awaited her at the end of it.
VIII.
When the alarms in the cortex begin to blare, Barry can't help the sinking feeling in his stomach.
It's too soon.
They have a plan for getting Chester's consciousness out but the rest is speculation at best, full of wishful dreaming and daring stubbornness. But Barry had to act. The fate of Central City depended on it.
Exhilaration thrums through his body as Barry sets his sight on the pulsating inky darkness that mars Central City's bright blue skies. The magnitude of this moment doesn't escape him – he was about to run into a freaking black hole – but it's largely overshadowed by the deep-rooted fear that coils itself in his gut.
No one knew what lay beyond the event horizon of a black hole.
But Barry Allen was about to find out.
With a swooping feeling in his chest, he alters his course upwards, the building's glass walls vibrating beneath his feet. Pushing off, he leaps towards the adjacent building, body tight as it flies just over the miniature black hole. Landing swiftly, he runs back down the side of the other building and completes the loop once, twice, over and over until finally –
"That's your window, go!"
With a stuttering breath, Barry plunges into the unknown.
At once, his very cells seem to squeeze, leaving Barry breathless. There's a roaring in his ears and a piercing pressure that presses against his skull and somehow, Barry knows that the suit is shielding him from the worst of it.
After a seemingly endless moment, the pain subsides and Barry's attention seizes on the writhing red mass that can only be Chester's consciousness. Around him, nebulous clouds of stars glint and gleam against the vast and endless vacuum of space.
The moment Barry reaches for Chester's consciousness, something shifts.
Like superimposed images, Barry watches wide-eyed as curious crystal clusters flicker into being, glowing softly and thrumming with quiet energy. They seem to come from thin air, jutting out at weird angles but beyond them, Barry can still see the nebulous clouds from before.
A strange lump of emotion catches in Barry's throat, one he can't even begin to unravel. But there was no time for that.
Behind him, he can still see the portal open behind him but there's no sight of Caitlin anywhere.
He calls her name and finds his voice has no echo.
Around him, the crystals glow brighter in response to his voice. Stepping closer, Barry reaches for a shimmering pink gem and gasps as a vision begins to play out on its surface. He sees himself holding up a key, Caitlin's face lit up in colors beneath a sky full of fireworks.
Another crystal shows him a vision that has Caitlin wearing his suit, light brown hair tumbling over the deep red fabric. The Barry Allen that hovers near her wears a stethoscope around her neck.
There's hundreds of crystals, some playing scenes that are familiar to Barry though they play out differently, others so far removed from their world that he can't help but wonder in just how many worlds their paths had crossed…
A dark blue crystal brings him back to that moment in the pipeline, Caitlin holding an ice dagger to his chest. He watches as she follows through on his taunts and has to turn away, bile in his throat.
"Barry?"
The sound of Caitlin's voice has him whirling, breath punching out of him at the sight of her.
Caitlin's expression crumples, half-sob half-laugh escaping her as she rushes forward and crashes into him. Barry rocks with the impact, arms winding tightly around her as he closes his eyes and breathes her in. The relief that crashes over him is warm and Barry can feel heat pricking at the corner of his eyes.
She's alive. Caitlin's alive.
"I heard your voice and thought I was going insane," she says, her words muffled as she presses closer. She feels cold in his arms.
"I'm here. I got you."
IX.
When Barry Allen runs into a black hole, his team can only watch in horror and in awe.
Chester's consciousness lies just beyond the threshold and theoretically, Barry should be able to get in and get out.
But there's no accounting for Caitlin Snow. Whether she's alive, where she is inside… the lengths Barry is willing to go to for her.
Ten seconds.
"Barry. Barry, can you hear me?"
There's no way of knowing whether Barry can even hear them but Iris has to try. Silence crackles over the comms.
Twenty seconds.
On the ground, Ralph can only stare at the yawning void that pulsates and contracts, a stain upon the sky. Joe closes his eyes and prays.
"Barry."
Thirty seconds.
Cisco chews on his thumb and watches the screen, a sick feeling spreading through his body. He wonders numbly if today was the day he'd lose another friend.
In one of Star Lab's training rooms, Cecile's nerves fray as she listens to Iris' pleas.
Forty seconds.
Something flies out of the void, a mass of writhing red energy that Ralph reaches for instinctively as it nears the ground. Chester's consciousness.
Turning his eyes back to the void, the team waits with bated breath.
But nothing else comes through.
The void disappears in the blink of an eye and Central City's speedster is nowhere to be seen.
In the Time Vault, a headline shifts: FLASH VANISHES IN BLACK HOLE.
X.
"Come on, we have to go before it closes."
But when he tugs Caitlin towards the portal, Chester's consciousness still in sight, she cries out. Clutching at her head, Caitlin feels her cells splitting, the pain intensifying with every step she takes towards the exit. Barry feels it a second later, a pain more intense than the one he'd felt coming in.
Almost immediately, he understands.
No one knew what lay beyond the event horizon of a black hole.
But this much they knew: Nothing can escape its gravitational pull, not even light.
Glancing down the path of crystals, Barry has an idea of what lies in wait for them at the end: a singularity. A place where spacetime touches infinity, where the gravitational field grows without bounds. A place where time itself ceased to exist.
He shivers with the knowledge and smiles wryly.
Gritting his teeth, he fights against the pain and makes his way back to where Chester's consciousness coils and twists. This, at least, would make it through. Grasping it in his hands, he weighs its heft in his palms and with a quick calculation, sends it hurtling through the void with all the force he can muster.
It winks out of existence and Barry hopes that someone from the team is on the other side to catch it and restore Chester's consciousness. Even more fervently, he hopes that Central City will be fine without him.
Caitlin must understand because she says nothing as he joins her. Together, they watch the black hole close, hands gripping tightly onto one another.
There was only one real destination from here, the path laid out before them.
But glancing at the cheery crystals around them and the lives that played out across their surface, Caitlin and Barry knew they had lifetimes to choose from and an eternity to get there.
Author's Note: IM SORRY. I DIDN'T KNOW HOW THIS STORY WOULD END OKAY! PLS DONT KILL ME 😭
I chose to keep the ending as open as possible because they're not really dead but they're not really alive either. Schroedinger's Snowbarry, if you will.
One of the common theories about black holes is that they're gateways to other universes and so the crystals were sort of meant to signify that. And just as the black hole responds to Chester, part of it is also responding to Caitlin (and Barry later on). That's why the crystals manifest in response to her thoughts and why Barry initially sees something very different than what Caitlin sees. His touching Chester's consciousness brings everything together.
Also I know that Barry makes it out in the show but I wanted to play up the ambiguity because realistically, no, he wouldn't be able to escape. The show really plays with the science in this but if we were to argue that he theoretically could, that the Speed Force would protect him, would he want to? Knowing Caitlin would be alone, knowing the kind of mindset he's in. This fic doesn't really answer that definitely but it plays with that idea.
Anyways I'll stop rambling now but please let me know what you think! :)