## Kindred

### Work Text:

Sitting on a rooftop beside Kara, both of them bedecked in their suits, Barry says through a mouthful of pastry, "I love this Earth."

Kara picks out another fresh-off-the-rack donut, adding, "I have to admit, I'm kind of jealous that this is a one-way visit. Remind me again why can't I open dimensional breaches?"

"S'actually a misconception," Barry says, swallowing another mouthful of donut. "See, dimensions – time, space – those stay intact. But universes, those – here." Grabbing four boxes of donuts, he scoots back so he can sit cross-legged on the roof, waiting until Kara joins him before opening up a box and organizing two dozen glazed donuts into a single stack. "These represent Earth. Each one vibrates at a slightly different frequency. From what I can tell, yours is slightly faster than mine."

Pointing towards the middle of the stack, he adds, "Theoretically, other Earths vibrate much faster than ours," sweeping a hand upward to indicate the top eight "Earths," "while the rest vibrate much slower than ours," back down to the bottom eight. "Then there are Earths that are, relatively speaking, neutrally fast," middle eight. "Base level. Everything is either faster or slower than my Earth; yours is slightly faster. Which is why," plucking a donut off the top, he adds with cheerful delight, "I crashed your party and not, say, an Earth where it vibrated ten times as fast." He shudders meaningfully. "Can you say vertigo?"

"Yuck," Kara agrees, plucking the next donut off the top and biting into it. "Bye, Vertigo."

Getting into the explanation, Barry flattens the stack to single-level concentric circles in the box. "This is our sun. Cosmologically speaking, it's basically our Earth," he says, holding up the centermost donut before replacing it. "These," sweeping his arm to indicate the entire conglomeration, "are other stars." Musingly, he admits, "Not the most accurate model, but something tells me you don't have a billion trillion more donuts."

Kara clicks her tongue. "Planning a superhero meetup?" she asks, amused.

Barry Post-It notes that in the mental compartment reserved for awesome ideas. "Someday," he says cheerfully, taking a donut and gulping it down in four bites. Kara retrieves one for herself before Barry snaps the box shut.

"Okay, so that's our universe. But here's the catch," stacking another box on top, he adds triumphantly, "there are multiple universes in the multiverse. Identical stars. Identical worlds." Another box. "Identical people, even. Closer you are to my frequency, the more likely we are to meet up." And another. "But the farther away we are, the less likely I can pass through these different barriers," tapping the box tops separating each of the boxes, "to get to you."

"Lucky me," Kara says with a smile.

"Lucky me," Barry corrects, swiping another donut from the topmost box before shutting it. "But here's the catch. I am here." Waving the donut, he prods it against the top layer of the box, meeting resistance and bouncing upward lightly in repulsion with each attempt. "Because we vibrate at different frequencies, it isn't easy for anyone to just cross over to another universe. To cross over, I have to actually vibrate at your frequency," phasing his hand through the box, he drops the donut into the next box down and holds up his empty hand, "to phase through." Retrieving it, he repeats the prodding gesture, adding, "Wrong frequency, no go. Right frequency," dropping the donut, he grins and sits back, finishing with a flourish, "Magic."

Kara claps slowly. A mischievous half-smile is the only warning Barry gets before she uses her laser eyes – laser eyes! – to bore a hole through the second box. Retrieving the same donut, she holds it up for his inspection before popping it into her mouth. "Magic."

"I wanna trade," Barry says earnestly, leaning forward with uncontainable enthusiasm because whoa-cool-do-it-again. "You can be the fastest woman alive, I just want laser eyes."

Kara laughs. "That's actually the second time you've referred to yourself as a woman. Oh-for-two."

Barry tchs lightly, shaking his head. "Without a doubt the coolest people in my life are women. Why can't I be one of the . . . gals?"

"Because you call us gals," Kara retorts dryly, leaning over to kiss his cheek, sweet, brief. "But it's endearing."

Barry grins, lazy, happy, reaching for yet another donut and tilting his head to look out over the city horizon, taking in the late afternoon sun.

Sitting on a rooftop eating donuts with Supergirl is definitely not how he imagined his Monday playing out. Waking up on the wrong side of the bed (literally: his inner speedster doesn't like to lie still for more than a few hours at a time, so he tends to shift and twist and roll until he falls off), he Flashed his way through breakfast and subsequently burned the toast. Then he got to the precinct just in time for one of Captain Singh's Allen! rants. Star Labs was a relief, even though Caitlin and Cisco were in full argument mode by the time he arrived.

Ultimately, Barry won the argument to try out the tachyon clip in the field. For two hours, it was a normal training session, complete with interludes to break up a robbery or rescue people from muggers. Feeling good about it, Barry decided to throws Wells' original I-do-caution-restraint commandment to the wind and see just how far he could push these babies.

Putting his heart into it, he surrendered to the Speed Force, letting it take him for a ride. It was like the ultimate caffeine buzz. Somewhere between the go-go-go-go! rush of pushing his own limits and howling with delight, he hit peak speeds in seconds.

Then he caught a glimpse of a woman falling down the side of a building and immediately took off after her, figuring he'd just run back into the city itself. Skidding to a halt in the desert, he panicked because oh-my-God-she's-on-fire.

Kara didn't even bat an eyelash. Barry didn't know whether to be more appalled or awed that she didn't mind being on fire. Then she took off, throwing her clothes at him, and he was so hooked.

I thought I was the impossible.

Shuffling back to the edge of the rooftop, Barry sits on the ledge, kicking his feet. Looking out over National City, he can't help but smile. "I love this Earth," he repeats emphatically.

"If we're keeping count, you're up to eleven," Kara says, sitting beside him, box of donuts in hand. "Care to make that an even dozen?"

"I love this Earth."

Humming, she teases, "You're such a tourist."

Digging an elbow lightly into her side, Barry reaches for a donut before pausing, grinning.

Kara narrows her eyes. "What?"

Digging his phone out of his pocket and scooting closer, Barry tugs off the cowl. Holding his phone out at arm's length, he puts an arm around her back. "I'm a tourist. Say 'Cheese!'"

"Secret identity," Kara sing-songs, smiling for the shot and laughing when Barry adds with an enthusiastic grin, Cheeeeese.

Bringing the phone back to himself, Barry checks the photo and laughs. The way her face lights up when she smiles is so worth any teasing about secret identities, Barry Allen.

Reaching up and tugging tug the cowl back down, he can't help but ask, "Why no mask?" Swiping another donut, he adds, "Aren't you . . . worried?"

Kara's lips twitch in a smile as she grabs her own donut. "People see what they want to see. Kara is invisible. Besides, Supergirl doesn't wear glasses or a bun." She shakes out her hair demonstratively, taking a bite. "It's the Batman problem."

Barry arches both eyebrows. "You have . . . Bat-men?"

"Batman," Kara corrects. "Rumored." Eyeing him, she adds with another bite, "As are multiple universes. I might have to look into that one."

Dead-serious, Barry says immediately, "I have to meet him."

"I'll let you know what my Bat-radar turns up," Kara promises dryly, finishing off her donut. "Superman's my cousin," she reminds him cheerfully. "You've heard of him before, right?"

Barry blinks uncomprehendingly, waving a hand in a so-so gesture to mask his complete ignorance.

Kara offers, "Big guy in red-and-blue, saves the city a lot, faster-than-a-plane? Nothing?" When Barry makes a noncommittal noise and squints to at least give off the appearance of remembering it, Kara arches her own eyebrows. "Really? Man of Steel?"

"Oh, I've met him," Barry agrees, wincing. "Learned something, too: don't punch the metal meta in the face. It hurts. A lot."

"You have an . . . actual man of steel?" Kara blinks. "Wow."

"We called him 'Girder.' His name was Tony Woodward."

Eobard called him 'Man of Steel.'

Realization hits Barry fast.

He knew about Superman.

He whistles, long and low. That is . . . ridiculously cool, actually. Eobard knew about Superman. Which meant, somehow, Superman was a factor of the future. All he can say is, "Huh."

"Huh what?"

Barry says, "Nothing."

"Barry," Kara warns, elbowing him.

Barry smiles, pops a donut in his mouth, and insists through the pastry, "Not telling."

And trust me, that future – will be here faster than you think.

He thinks, If there's a Superman in my future, then there might be a Supergirl, too.

He can't not smile, yelping when Kara gives him a little shove. "Hey. You never explained the Batman thing," he defends, one hand on the rooftop to steady himself.

Rolling her eyes, Kara settles her head against his shoulder. "It's easy. I'm in one room. Batman isn't. Therefore, I am Batman."

"Really explains your sunny demeanor," Barry agrees solemnly, wrapping an arm around her waist to steady her. "So Kara's in one room. Supergirl isn't. Therefore, you are Supergirl."

Kara laughs. "Exactly. You'd be surprised how well it works as a cover. It's ridiculous; I could hold up a picture of Supergirl and they'd do a double-take. Glasses and hair buns, Barry."

"Cisco's going to be so disappointed," Barry muses. "He worked hard on this suit."

"You can keep the suit," Kara allows, topping off the box. "Just leave the cowl off."

"Mmm." Reaching over for the second box, Barry props it open and lets her have first dibs before Flashing down its contents. "Tell me about your sister," he prompts, pulling out the third box and letting her have it. "Alex, right?"

"Uh huh." Kara chews thoughtfully on a donut, not lifting her head from his shoulder. He can feel the movement, feel the warmth radiating from her, a living space-heater like him. It's nice; he's always been up for hugs but being with someone as physically capable as he is is even headier. If not stronger, he muses. They haven't actually raced – yet. He doesn't know if she's even stronger than he thinks she is. It wouldn't be the first time a superhuman exceeded his expectations.

"I . . . Alex is my whole world," Kara admits. "I mean, I have a life outside of her, but I can't imagine a life without her. When I . . . became Supergirl, she wanted me to stay safe. Stay low. Stay Kara, not Kara Zor-El. I was mad at her, but I can see why she pushed back. It's not easy. And. . . ." exhaling, she admits, "and I'm not always good at what I do. But Alex believes in me. She forgives me, even when I don't deserve it. And at the end of the day we're sisters."

"What's she like?" Barry prods.

Kara says, "Smart. Funny. Kind, but cold shoulder-y at times." Laughing – and not without bitterness – she adds, "Alex is . . . the kind of person you want on your team. Because I know she wouldn't make a bad decision in the heat of the moment. She's too careful. But sometimes that . . . calculation makes her a little hard to empathize with. She doesn't always get that the needs of the many don't outweigh the needs of the few."

"Or the one," Barry finishes. When Kara lifts her head and looks at him, he smiles. "Cisco." Saluting in Vulcan, he adds, "Whenever we watch Wrath of Khan he always quotes it. He loves I have been and always shall be your friend." Sighing affectionately, Barry reaches up to rub his own face. "They've gotta be worried sick."

"It's only been a few hours," Kara reminds gently.

Barry nods, dropping his hands. Reaching for another donut. "I'm going to miss these," he murmurs. "They're just so fluffy." Taking a bite, his eyes all but roll into the back of his head with pleasure. "How?"

"Do you not have actual donuts on your Earth?" Kara asks, amused. "I thought those were a universal constant."

"Not these donuts," Barry says emphatically. Swallowing, he asks, "You never said – where is Alex, anyway?"

"Not sure," Kara admits. When Barry tilts his head, she adds vaguely, "She's on a mission and in typical Alex fashion, she didn't leave a lot of bread crumbs to follow."

"I hope it gets resolved soon," Barry says.

Kara squeezes his knee. "So who's Cisco?" she redirects. "You've mentioned him twice now."

"One of my best friends," Barry explains. "He's an engineer and probably the dorkiest human being in existence. Best friends with one of my other best friends, Caitlin Snow. Caitlin is . . . she's the rock. The one who keeps us sane and happy. We wouldn't be a team without her. Cisco and I just can't do it on our own; she helps balance it all out. You would love Caitlin," he adds, looking at her. "She's been through a lot, but she's still this incredibly compassionate person. Just don't dislocate your shoulder around her." Rubbing his own in remembered discomfort, he grimaces. "Or do, but be prepared."

"I will try not to dislocate my shoulder on your Earth," Kara vows dryly. "Should I ever make it to your Earth." Cocking her head, she looks at the discarded boxes of donuts. "Think you'll ever come back?"

Without hesitation, Barry says, "Of course." Then, teasingly, he adds, "For all the family reunions. Especially for my three favorite cousins."

Kara laughs, big, open, infectious; Barry laughs along with her. "They like you," Kara says, knocking his shoulder lightly. "They were willing to cover for you. Badly. But the thought counts."

"It does indeed." Smiling, Barry looks out at the golden light, feeling the cooling breeze on his skin. "Why is it so perfect here?" he asks.

Kara tips her head against his shoulder again, like she can sense the sand trickling away from them, all too fast, and wants to savor their time together while she can. "It's not," she says simply. "You should know that. Sparky and Shrieky are just the tip of the iceberg."

"You should definitely keep those nicknames," Barry urges.

Kara snorts. "How did you come up with Girder and Pied Piper?"

"Cisco," Barry says simply.

"Ahhhh." Plucking the last donut from the third box, Kara asks, "Why did you help me?"

Barry shrugs gently. "Superheroes have to stick together," he explains. Unable to suppress his own amusement at just being here, in National City, in what is turning out to be a truly spectacular Monday after all, Barry adds, "And I did think you would go splat if I didn't catch you."

Kara squeezes him appreciatively, a half-hug. "Thank you."

"Any time," Barry says seriously.

They spend an uncountable slice of infinity on the roof watching the sun sink lower and lower, feeling at ease, at home. And Barry thinks, I am home.

Their Earths overlap. Intersect. Occupy the exact same space.

I am home.

Still: he's not there yet. And want it though he might, he can't stay here forever. He has to go home.

At last, it's time.

It aches in his chest to finally stand, to have to pack up the wreckage of their donut-spree. To have to pack up the end of their adventure, with only memories and warm hugs to linger in the hours afterward.

But he does have one final request.

Kara obliges, insisting that he return the favor, and the two superheroes part ways in that big open field with a hug, aware of the universes separating them but keenly aware of each other's presence, too.

Lying in the grass under a starry sky a billion trillion stars away, Barry can almost pretend she's there with him. Eyes closed, he can almost hear her, almost feel her. But when he does finally concede to the coolness settling in his skin to retreat to his room, he strips off his shirt and takes a moment to savor the Sharpie-inscribed message on the back of it.

Live long and prosper, Barry.

~Supergirl

Sinking onto his back on the bed, he smiles at the ceiling, thinking about his identical, if reversed, inscription.

Live long and prosper, Kara.

~Flash

He doesn't know if they'll see each other again. But somehow, it feels okay, knowing that they've left their marks in each other's worlds.

It says: Whether or not I'm here to say it in person, I'm here for you.

For Barry, it's exactly what he needs.

. o .

Over the years, they gather enough photos to fill a weighty album, enough memories to fill a hundred lifetimes, and enough donuts to feed a small universe.

They do have superhero meetups. Barry does get to meet Batman. And Kara does get to visit Barry's world.

But above all else, when they reunite, it is unexpected, it is good, and it is welcome home.

Of all the things Speed gave Barry, it's the ability to traverse the multiverse that he savors the most.

I'm home, he tells Kara and Winn and James and even Cat in hard hugs and teary greetings because it's been so long and I-didn't-think-you-were-coming-back and what a relief it is to be here.

There are a billion trillion other stars, but no matter which Earth they're on, one thing is always true:

I have been – and always shall be – your friend.