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Catalyst

Summary:

Outside of time, Leonard Snart makes a choice to sacrifice himself for the sake of a universe he thinks he’ll never know.
Across the multiverse, Barry Allen runs to save a future he thinks he won’t get to have.

The new reality is one they both learn to navigate together.

(A post-Infinite Crisis AU)

Notes:

Knowledge of the Infinite Crisis crossover event not required, but there will be spoilers in future chapters!

This is probably the most ambitious thing I’ve tried to write in a longass time, and I anticipate I’ll hit more than a few snarls as I pull everything together. I wouldn’t have tried a word of it if I weren’t endlessly inspired by the beautiful fanwork in the ColdFlash fandom - if you’ve ever written, drawn, fanmixed, or even just posted to holler about feels for this ship, thank you; so many of y’all have inspired me to finally try my hand at contributing too, and I hope if nothing else EVERY PERSON who takes the time to read this knows how very much I appreciate you ♥

Enormous thanks to the lovely folks who kindly beta-read and whose feedback helped me finish this first chapter: Luna Shimizu, Hidden_In_Smoak, Fancy_Dragonqueen, and blueelvewithwings.

And all my love for the ColdFlash Discord server, y’all have been a bastion of joy in a time when I’ve really needed it.

Chapter 1: Oculus, Aftermath, and Awakening

Notes:

(See the end of the chapter for notes.)

Chapter Text

Leonard Snart was no stranger to pain. It had been years since he’d flinched at the promise of harm, and could still hold someone’s eye down the barrel of a threat while cutting them with words sharper than any knife. Had to. It was the only way he’d survived long enough to be standing here; outside of time at the end of the universe, with his hand stuck in his own tombstone as he watched the closest notion he had to ‘friends’ sprint away toward safety.

Mick’s last conscious look of confusion had just begun contorting into something like fury when Len’s fist had connected. Still, an echo of his partner’s voice threatened him against whatever stupid thing he was about to do, but Len refused to hear it. His last human touch came from the reformed assassin who turned out to be the one who stole a kiss from him. Sara’s final fleeting glance wasn’t pity; she held his eyes with a calm understanding that Len knew would haunt him if he had any longer to dwell on it.

Best that he didn’t, he supposed; instead, he braced himself for whatever flashbang of pain would accompany this idiotic sacrificial last hurrah. He didn’t want to pinpoint the moment he knew this was how he’d go out. He suspected if he could flip back through his own greatest hits, he’d find the marker tucked between pages dedicated to his sister; shaped like a crooked grin clad in lightning and red leather.

But that had all been part of their orchestration too, hadn’t it? All of them making puppets dance for some grand universal bureaucracy. He wrenched at the bitter resentment and fury roiling through him to help steady his hand.

“There are no strings on me,” Len bit out as he savored the last moments of his greatest score; stealing back free will.

Blinding white surrounded him — almost comfortably familiar, like his cold gun’s glare — then every sense was awash in too much. Explosive tinnitus ricocheted through him as if he’d become a new state of matter, his sense of self winded by the onslaught.

Len wondered if this was where most people would have screamed.

 

 

This part of death felt a bit like riding a cosmic roller coaster, forever climbing up toward an inevitable drop.

He’s counting the seconds reflexively, and it’s been nearly a minute when he feels the full-body dissonance rattling through his atoms begin to subside.

After eighty-three seconds, it’s as if his entire body is pins and needles awakening from having been asleep - discomfort, but not pain.

At one hundred and seventeen seconds, Len runs his body through the same checks he always does when evaluating for injuries - slow methodical stretches and flexes, taking stock.

At one hundred and forty-three seconds, Len opens his eyes.

In Len’s youth, Lewis had scoffed disdainfully at the bright fantastical fictions Len gravitated toward, which - of course - ensured that he’d read every scrap of science fiction and fantasy he could get his hands on. Countless stories had woven visions of wonder in his imagination over the years, some of it even taking root before the harsh reality of his life tore the dreams of stars from his night skies. Impossible things had become commonplace lately in the world he thought he knew, running through his city like the beat of a new pulse. Then the Waverider had shown him the timestream. The first night he’d tried to settle into his bunk aboard the ship, he’d felt a stuttering gasp from someplace buried deep inside himself that made every night a little less sleepless, and a little more hopeful.

None of it prepared him for how the universe wrapped around him now in an infinite embrace.

It wasn’t just endless spirals of starlight and empty black, it was everything in-between.
All the life.
Countless lifetimes, linked together across civilizations and species and planets, time and dimensions and multiverses and—
Somehow, in all of it, a salty thief from a merry band of misfits bumbling through time had set off a cascade through everything when the Oculus had ceased to be.

Leonard Snart saw the flow of the universe and he wept.

A sense of serenity eventually pulled his shaking breaths back to normal. His internal count had long since fallen silent, overwhelmed by the enormity of understanding what scale in a cosmic sense meant.

The ripples of their actions spread through all of it. Len reeled with the revelation that if this was the culmination of every miserable second of his life, it had been worth it to do this. Len felt himself drifting through introspection as he tried to process the unfathomable fact that his actions at the end of his criminal blip of a life had changed everything.

His own cocoa-warm words echoed back to him from a living room forever ago, “Sorry, I’m not interested in being a hero.”

“Well you’re doing a pretty lousy job of being a villain this week,” Barry had responded then, still vehemently believing so stubbornly in Leonard Snart being someone he wasn’t, not yet - not then, anyway.

The words were chased by a repetition, but Barry’s voice was softer in the refrain, holding a note of fond teasing that hit closer to admiration than admonishment. “Well you’re doing a pretty lousy job of being a villain this week,” Barry smiled kindly in a moment that hadn’t happened for this Leonard Snart.

It reminded him of the way Barry had looked at him in Siberia — Len realized: Barry knew.
The universe crystallized Len’s certainty that the Flash he’d met then had already done his mourning for Captain Cold.
The ache in Barry’s gaze Len had attributed to worry for Iris suddenly sent him second-guessing if the Scarlet Speedster had been, in his way, saying goodbye.

Len choked out a wet laugh at the thought that the Flash had bent the rules of time to take his chilly nemesis on one last heist.

It was a kindness Lisa deserved, but wouldn’t get. Len knew Mick would be the one to tell her, in his haltingly gruff way.
She’d know before he said a word, though.
It wouldn’t surprise him if Sara insisted on going along, too. Lisa wouldn’t appreciate her at first, but Sara seemed impervious to the Snart brand of cold shoulder. He could see them becoming dangerously good friends once they figured out how to sharpen their grief into purpose.

Len hoped Lisa would aim herself toward a better, kinder horizon than the one they’d come from. At least everything he’d been saving up for her over the years could help ensure she never had to work for anything if she didn’t want to. She could choose for herself now; no invisible hand could tug her strings any longer.

And so he spun, revisiting memories of himself until he realized he was knowing and seeing things that Leonard Snart couldn’t possibly know or see.

Lisa’s practice in an ice rink Len had never visited, her hair held trapped by a wide headband after she’d decided she wanted to cut her own bangs.

Mick with a baby in his arms and a smile that held more love than the man himself had ever known.

Sara Lance falling, Ta-er al-Safher rising.

Ray with a magnifying glass an inch from his nose as he delicately pressed the tinning wire to the tip of a soldering iron.

Rip complaining about getting out of bed, a woman beside him laughing.

Jax slamming his shoulder into a practice dummy as the scent of fresh-cut grass chased him down the field.

Stein raking a hand through his hair as he stared down a formula as if demanding the solution from the cosmos itself.

The Hawks, as they were at the start of everything, kohl-rimmed eyes smiling under a desert sunset.

His mother’s smile for the man his father once was.

A young boy screaming for his mother in a lightning storm.

The copper tang painting Len’s teeth from the solid punch Mick owed him but he’d never get.

Lisa laughing so openly, so honestly, as she leaned into someone else’s shoulder with a fondness that seized in Len’s heart.

CSI Barry Allen in his lab, hand on a chain moments before the universe tilted back his chin with a bolt of change.

On it went, flitting through moments like someone was browsing channels on TV and he had no idea who held the remote.
When it settled, Len found his cognizance focused on the docks of Central City, then a familiar bar nearby.
The neon cut out his silhouette as if he were pasted from the pages of a comic book, and Mick stood beside him gathering words between his brows.

Mick had ground out, “You’re the best guy I ever knew. You may not think you’re a hero, but you’re a hero to me. You got that?”

Len remembered the ghost of something he couldn’t quite define back then when he responded, “Yeah. I got it.”

Mick parted with an abrupt, “See ya ‘round,” and Len had turned the encounter over for hours after. It hadn’t fit then, but now—

Ah.
So that had been Mick’s goodbye.

But then—

There was more, endlessly more that threatened to overwhelm him; the universe held him away from it, though, and he knew the vast potential of reality splintered and branched in ways that would undo him If he let himself look. His sense of rebelliousness was quelled by a greater bid for self-preservation, whatever that even meant any more, and Len didn’t push.

His focus shifted, soothed, recentered as Len felt something like his heartbeat hammering in his temple. The sight before him now was vignetted, and he was alone in a safehouse staring at nothing in particular, jaw working in thought. There was nothing remarkable about this night or this moment, but it had dug in roots that haunted him. Len had been alone with himself and his own thoughts too long, cracked open in introspection that made him realize he wasn’t sure he knew what it felt like to be happy.

The next day, he’d been counting successful seconds on the latest score when he was knocked to the asphalt by the impossible.

Spiraling arms of galaxies wrapped around him in a way that was as unsettling as it was comforting, and it felt almost as if there was a gentle hand on his shoulder turning him to look— there.

A plasma-bright yellow pinprick of motion danced across his vision and Len felt goosebumps rise like they always did when the speedster ran into his orbit. It wasn’t like looking down on Earth in the serene way of all the documentaries; it was more as if a maelstrom of events coalesced around him. The Flash sped through them all, and sometimes more trails of lightning-bright plasma ran alongside him, all in different hues and crackling with barely-contained potential. Len’s sense of time had redefined itself, but he knew following the flow of that lightning went on for a while as he watched and waited to see what happened.

He’d been too intent to initially notice when the rest of the universe around him softened, then dimmed, into nothing.
The yellow-bright fork of lightning branched out to split, then rejoin with itself; again, then again, countless paths seeking something across all of it in a burst, tracing Lichtenberg figures through realities.

He heard Lisa scream.

His consciousness whipped toward the direction it came from and found nothing but an empty echo.
Her voice came again, a soft gasp — again, he found nothing.
Len lurched toward the realities the universe had gently said weren’t for him, and in its enormity, he’d acquiesced without truly understanding. Now, though, he pushed past the universe’s warning, and with the deft instincts of the thief who’d stolen back free will, Len pilfered those realities to find his sister.

In this one, her Olympic golds shone brightly from their display in the midday sun filtering in through the windows.

In another, she playfully wrestled with a younger brother and rubbed a knuckle affectionately into his familiar widow’s peak.

In that one, she blew a kiss chased by a Cheshire grin half-hidden behind slitted goggles, cool blue light tracing her cheek from the gun she held aloft.

A mayor, a singer, a dancer, a mother, a brother, a dazzling heroine, a feared queen of the underworld; spirals of potential people who were all their reality’s version of Lisa Snart.
In many, he saw snatches of himself and felt something crash in his heart.

Another sound of alarm reached him. Whomever that Lisa had been, she was gone — no, her reality was gone.
An angry curse cut off mid-breath, chased by a defiant yell, joined by her furious scream of, “NO!” — Lisa’s voice called out from one reality after another before his sense of her lessened when they fell silent.

Len tore at the universe, demanded an undoing, and felt that whisper of something like a hand guide his attention away as if shielding him from the worst of it. He lashed out, howling wordless and primal, curling around the vestiges of what he sacrificed everything to protect.

Lightning danced around him, a yellow-bright streak that seemed to trace the shape of each reality; as if it could be a shield from whatever was coming if only it could move fast enough.

It couldn’t.

Snatches of despair and fear and darkness crowded into the spaces where realities once were, nothingness yawning in a slow creep to consume more. Around Len, the arms of the universe felt lesser, and dread shook in his instincts the way a bad situation always did. The phantom band of a ring no longer around his pinkie finger was a reminder and warning he wished he could heed.

One by one, the realities ceased, and through them all a bolt of impossible lightning tried to run fast enough to stop it.

The multiverse shuddered like it was dragging in one last gasp, and Len felt something like the pulse of his soul stutter. Too-familiar blinding white shot through everything again. This time, though, a flicker of yellow danced on the edge daring hope to flare in him.

 

 

Leonard Snart woke up slowly, luxuriating in the whisper of an embrace that lingered in the curve of the bedsheets around him, perfectly languid and sleep-warm. Soft light illuminated the room in the diffused glow of an early morning. Drawing in a conscious slow breath, he reveled in the faint notes of lavender and spice from the aromatherapy aid he used to ease his thoughts before bed.

His waking mind was slow to thaw, so as he rolled onto one side Len blinked his eyes open to survey what was eerily familiar yet unknown to him. The room had all the hallmarks of his taste, functionally minimal but neatly showcasing personal touches that were as close as he ever got to making a place into a home. An old photo frame sat beside a battered copy of The Scarlet Pimpernel, a hook on the back of the door suspending one of his holsters. Len’s fingers curled around the familiar shape of a pistol tucked against the mattress, where he always keeps it.

It had all the right traits of a room he’d call his, but he had never been here before in his life.

Speaking of the whole life thing.

Len slid from the bed to his feet with silent ease. The bare hardwood beneath his toes didn’t creak as he moved about the room, weapon in hand, and listened at the crack of his door. Part of him was on autopilot as he investigated his surroundings, eyes darting to catalog every corner. The other part of him still felt like he was waking up from whatever the fuck had happened with the Oculus at the Vanishing Point. If he closed his eyes, the afterimage of lightning dancing through nebulas still lingered; none of this was right.

Slowly, Len opened the door of the bedroom and continued his sweep of the space. The short hall first revealed a dark doorway into a bathroom, but otherwise led into a living room and kitchen. An apartment, then. Taking stock, Len crept silently through it all, the muzzle of his pistol leading where his gaze followed. Everything fit as if he’d lived in this place for months.

He began investigating more thoroughly, all the while turning over his recollection and trying to make sense of it.

Footsteps outside made him pause, the gait striking a familiar staccato of sharp heels on low-pile carpet, and Len’s pulse leapt into his throat at the sound of a key in the lock.

Lisa let herself in like she always did, with the decisiveness of someone who knew she had nothing to fear, the scent of coffee and cinnamon following in her wake. She launched into a rant involving how the coffee shop messed up her first order, could you believe it, so she’d had to wait for them to fix it but at least she’d gotten free pastries out of it and—

Len watched her move through the kitchen like a comfortable force of nature, and if there was a little hitch in his breath, she wasn’t paying attention to him to see it.

She propped herself against the counter and sipped at her coffee, finally looking at him. Len could tell the moment she noticed something was off. Lisa frowned, “What’s wrong?”

He had years of practice to fall back on when he sidestepped the truth with his response. “Thought I heard something, but it was probably just one of the neighbors.” Len relinquished the numb grip he had on his pistol, setting it down on a section of nearby countertop.

As he reached for the cup she had brought for him, Lisa’s keen gaze followed him. “Just the neighbors?” She asked, open-ended; giving him the ease of her doubt because she always did.

Len stalled with a sip to revel in the flood of warm spices from fresh chai with a hint of honey. “Probably,” he hedged, before sipping again, his aloofness perfectly calculated down to the jut of his hip against the lower cabinets.

For anyone else, that would have been enough; he was an excellent liar. But she knew him too well.

“Lenny,” she started in a way he’d ached to hear again, “if this is about—”

“It’s about the Waverider,” he cut her off, a thread of still-raw truth to it he hadn’t expected to sneak out. She wasn’t expecting him to say anything at all, but she waited patiently for him to continue.

The cup in Len’s hands probably should have been a warm comfort to him, but it instead felt numb where he tried to keep his hands from going white-knuckled around it. Holding it was a cheap anchor, he knew; he felt half-gagged if he couldn’t speak with his hands flitting through the air to add punctuation as he went, but he knew it would just give more away than he was ready to discuss at the moment.

“I’m still,” he took his time to find words to encompass what, “.. processing things. I just need some time, Lise, before I’m ready to talk through it.” It was more honest than he initially realized, but let his brevity settle into the air between them with a hesitant flick of his gaze to read her.

She regarded him with the open concern he expected, and the patient smile he never deserved. “Okay, Lenny. You know I’m here for you no matter what, though, right? Don’t make me threaten you with a hug. Even if I end up frosted, it’d be worth it.” She aimed a playful pout his way.

Len visibly relaxed at her shifting the mood, and he offered a small, but genuine, smile. “Love you too, trainwreck.”

Lisa laughed fondly, digging into the bag to retrieve one of the cinnamon pastries. “Jerk.”

They spent the morning more domestically than Len ever thought would be possible; it was mundane and uneventful and boring and perfect.

When he finally does hug her a little tighter before sending her off, he keeps the crash of emotions at bay until he closes the door quietly behind her, listening for the sound of her retreating footsteps and concentrating on his breathing for eighty-seven seconds. Then he’s sinking to his knees as a breathless sob wrenches free of him.

His vision blurs with tears, and an unfamiliar numb tingle traces over his cheeks. Len reaches up to scrub the heel of his palm across his eyes, puzzled by the odd sensation.

Blinking down at what he sees in his hands, he gets to his feet and is in the bathroom within moments, hand slapping at the wall to find the light switch. He squints against the sudden brightness but stares at himself in the mirror.

Frost rimes the tips of his eyelashes in soft white, and the thinnest trail of ice still streaks one cheek in a tracery of his fallen tears. His hands, he notices, look no different, but...

Len moves quickly back to the kitchen, snatching up where he’d abandoned his cup of chai after half-strangling it in an attempt to ground himself through Lisa’s questioning. He all but rips the lid free to inspect its contents, and finds the liquid frozen.

A shuddering breath hitches as Len stares down at his frozen drink, and it feels like the dam retaining his tenuous hold on his composure cracks.

“Fuck.”

Notes:

SO UH
HERE WE GO

I absolutely am very much outside my comfort zone with writing this but I really hope folks enjoy it.

I’ve got this story mostly outlined and am trying to keep a chapter ahead before posting as I go, which I sure hope doesn’t end up biting me in the ass. Rough estimate is around 10 chapters total right now, though!
Thank you so very much for reading through this! I’d be delighted to know what you think ♥

You can also find me on the ColdFlash Discord server, or at hautecoldture.tumblr.com