A Very Crossover Christmas

Well, we've reached that time: Day 12 of a 12 day series. Thank you so, so, so much – truly, from the core of my being – for all your kind words of encouragement throughout this journey. I means everything to me, so thank you.

Tomorrow I'll be launching, as requested, an "8 Nights of Danvers Chanukah" fic that I'm extremely excited about, so please tune into that, as well as to my already ongoing "I Didn't Know You Were Into Girls" Sanvers one-shot series.

Happy and safe holidays, and thank you so much again for making this writing experience absolutely wonderful 3

And without further ado: Kara invites Barry and Oliver's teams to come spend Christmas with the Superfriends!

Alex had promised to be nice.

She just hadn't defined nice when she told Kara that she wouldn't beat Barry Allen into a pulp for recruiting her to help him fight off an entire invasion force of aliens on his earth.

"It's Christmas, Alex, and I'm okay, it all worked out!" Kara had told her, for the thousandth time, before Barry and Oliver's teams jumped out of the interdimensional rift and into her ridiculously festive living room.

Well, it might be Christmas – there might be champagne glasses in everyone's hand and there might be a rather rowdy game of "which earth has better Christmas music" going between Cisco and Winn – and Kara might be okay – okay enough to have thrown what was sure to be the most superhero-full Christmas party of all time – and it might have all worked out, given that there didn't seem to be angry aliens clawing their own way through the portal into this earth.

But that didn't mean that Alex Danvers didn't have Barry Allen backed against the refrigerator – the Flash, the fastest man alive, legendary superhero – cowering.

Iris stepped forward but James touched her arm lightly. "She won't actually hurt him," he whispered.

Iris arched an eyebrow.

"You sure about that?"

Caitlin's eyes were wide, Cisco's mouth was open, Winn's eyes were downcast in sympathy for Barry, and Sara was smirking, dragging her eyes slowly up and down Alex's body, making Maggie frown and shift closer to Alex – but not that close, because it generally wasn't safe to approach her when she was this angry.

" – the height of irresponsibility," she was saying, holding Barry up by the collar, "not to mention massive selfishness and pure tactical stupidity. Do you have any idea how stupid your plan was? One alien against an army, when we have an entire organization here that's experienced in these things, an entire army of our own whose entire lives are dedicated to stopping the kind of deadly threats that you so willingly through my sister into, alone and without backup? And don't – "

She renewed her grip on his collar as Barry tried to stammer out words – "don't even try to tell me that you were her backup. How could you possibly back her up when I hear she beat the ever living shit out of you all, at once, without even breaking a sweat? So how could you possibly protect her against an army? And I don't care what your city thinks of you, I don't care what kind of hero you think you are. The next time you need Kara's help, you do not whisk her off on her own, you do not take advantage of her good, eager to help heart. You get me, you get my team, you get my people, people whose lives are dedicated to doing what your teams are way in over their head even contemplating. Because so help me, if you ever bring my sister on a mission like that without me there to watch out for her, I swear on everything you love, a brutal alien invasion force is going to look like kindergarten next to what I will do to you. Do I make myself clear?"

Barry whimpered for a moment or two, wondering if her question constituted permission to speak or to just nod meekly. He opted for the second, and she released him.

"Eggnog?" she asked, swiping a glass from the counter behind her and pressing it into his hands with a massive smile on her face. "You look like you could use some." Barry stammered something that he hoped was recognizable as English, that he hoped Iris, Caitlin, and Cisco didn't hear just as the squeak that it was. By the looks on their faces, he had no such luck.

"You make yourself quite clear, Agent Danvers, so let me return the favor: you don't get to threaten anyone on my team without going through me." Oliver's voice was calm, his face completely neutral, as he stepped up to Alex. Diggle groaned into his hands.

Alex gazed up into his eyes as Barry tried to touch Oliver's arm. "Ollie, really, it's okay, you'd get the same way if it was Thea, I understand, it's fine."

"No, it's all good, Barry. Oliver Queen, right? Arrow?" And before he could even blink, Alex had him, too, up against the fridge – good thing for Barry's super speed, else he would have been crushed by Oliver's back – and Felicity let out a small gasp.

"I like this girl. She like this in bed, too, Sawyer?" Sara wanted to know, loudly, and Kara's ears turned an even deeper shade of red. Maggie spluttered and Alex just dug deeper into it, her forearm against Oliver's throat.

"You want me to put the threats through you, fine. You don't ever tell my sister she's not good enough to fight, you don't ever tell her she's not to be trusted, you don't ever make her feel like a reject, you don't ever tell her she's not strong enough to keep up with you."

"Um… Alex?" Winn hid behind a facepalming Kara as he spoke. "You can't… threaten Barry to not let Kara fight on her own and then threaten Oliver to let Kara fight on her own…"

"You wanna watch me, Winn?"

James leaned into him. "Man, you know better than that."

"I apologized to your sister, Agent Danvers. I was wrong to tell her not to fight. Now, I was under the impression that this was a Christmas party. I don't know if it's different on this earth, but in mine, Christmas parties don't tend to include threats of bodily harm."

"Seriously, Oliver? Yeah, they do." He rolled his eyes toward Felicity, who was shrugging innocently.

Alex yanked her forearm down from pinning him against the fridge, and Sara let out a groan of disappointment. "I don't like you," Alex told Oliver.

"Funny thing is, I like you, Agent Danvers. Someone that protective of her kid sister? We probably have a lot more in common than you'd like to think."

They stared at each other for a long, long moment before Alex found what she was looking for in Oliver's eyes. "You get eggnog, too," she relented with a grin after a few moments, and he nodded his gratitude as he accepted.

"Are we… done with the Kara's sister going What is the location of the rebel base? on people now?" Cisco wanted to know. Silence and furrowed brows greeted him from every side. "Come on, there's no Star Wars on this earth?"

"Star what?" James teased, and Cisco blanched.

"What kind of hell hole did you take us to, Bar?"

Winn took a few deep breaths in his best Darth Vader impression, and Cisco breathed again. "Ahhh, you really had me going there for a second," he shoved into James, who laughed and flipped back on the endless loop of Kara's favorite Christmas music.

"How's your neck, man?" James asked Barry after Winn started using words with Cisco, Felicity, and Caitlin that James couldn't quite keep track of and after Sara gave up on trying to get him, Oliver, and Digg to compare bicep sizes.

"For science," she'd argued before Digg put his arm around her shoulder and led her away.

"Well, you know, super speedy healing, but… a little stiff." They both scanned the room, bustling with people and laughter and snippets of surprisingly excellently sung Christmas carols and eggnog and champagne, until they found Alex sprawled on the floor in a corner with Kara, Iris, and Maggie.

As Kara spoke – probably telling Iris a story that Alex and Maggie had lived through – Alex leaned over to whisper in Maggie's ear, stroking her hair and touching her cheeks and kissing her temples before grazing her lips with her own.

"Awwww," Iris interrupted Kara's story, and Kara adjusted her glasses furiously, looking away but smiling a megawatt smile at seeing her sister so… relaxed.

For once.

"How does she do that?" Barry asked.

"Mm?"

"That." He nodded his head toward Alex again, who was giggling now, eyes wide, her hands clasped together vulnerably at her chest, as Maggie told Iris something or other that was making Alex's ears go red, all the while sweeping Alex's hair out of her face with gentle fingers.

"You mean go from homicidal DEO agent to completely doe-eyed nerd in .02 seconds flat?"

Barry chuckled and nodded, and James smiled, taking a long sip of his eggnog while watching three of the women he cared for most bond with the woman who was Barry's entire world.

"Honestly? The answer's simpler than you might think."

"What is it?"

"Maggie Sawyer," James said simply, and as Barry caught Iris's smiling eyes from across the room, he suddenly understood Supergirl's sister a lot better.

When the oven chimed, announcing the readiness of the cookies within, Kara squealed and leaped up, dragging Alex with her for help. She nearly collided with a bemused, eggnog-sipping Diggle in her eagerness, and he chuckled and shook his head at Kara's over-the-shoulder apology and Alex's good-humored groans.

"John!" Iris called him over and he crouched down next to the women.

"We haven't properly met. John Diggle. I work with Oliver."

"Maggie Sawyer, NCPD. I uh, work with – "

"A combination of Supergirl and her sister, it seems," he offered graciously, and Maggie nodded, clinking her glass against his.

He sipped deeply and shuddered. "I think Sara spiked this even more than it already was," he chuckled.

"So Maggie, you don't have like, a secret identity or anything either?"

Maggie chuckled at Iris's question, letting her eyes wash over their friends, old, new, and newer.

"Nope. Not a superhero, not technical support, not quite just the girlfriend, but…"

She shrugged and Iris nodded knowingly.

Diggle chuckled and watched Oliver watching everyone else, body alert but eyes relaxed, if confused by the joy around him.

"I think we've all got that title, Maggie, you, me, and Iris: not quite just the girlfriend," Digg told them, sipping his eggnog gingerly.

Iris snorted and Maggie doubled over with mirth.

"We should get jackets," Iris wheezed, and Maggie slammed the floor with her hand.

Oliver, Barry, and Alex all glanced over at them quizzically.

"They're not… talking about us?" Barry wondered aloud. Felicity followed his gaze as Alex walked over to where she and Barry were standing.

"No. If they were talking about us, they wouldn't be laughing like… that…"

Felicity tilted her head and squinted across the room at Digg, Maggie, and Iris, the latter two now clutching at each other to keep from collapsing completely as Digg acted out some kind of writing on the back of an imaginary jacket.

"Yeah, they're definitely talking about you guys. For sure."

Barry took an unsteady sip of his eggnog, just as Sara strolled by. "Careful, Allen. Might be too strong for a teenager."

"I'm not a – I'm immune to alcohol, I – Sara!" But Sara was already gone, tugging Alex by the crook of her elbow near the Christmas tree.

"What?" Alex asked, eyes still on the laughing trio in the corner.

"You gonna slam me against a wall, too?" Sara's eyes twinkled, and Alex spluttered.

"I… I think my girlfriend would have something to say about that." Sara smirked and glanced over her shoulder at Maggie.

"No one's saying she couldn't come, too."

Alex spluttered again, and Sara's smirk changed into a warm smile. "You're cute," she told her, like she'd told Felicity soon after they'd first met, surprised by the awkward warmth she was finding in such a fierce soldier.

"But no, seriously, um… I just wanted to say…" Sara fidgeted, and Alex watched her closely. "Look, I know what it is to be protective. Of a sister. I…" Sara's eyes darted around the room rapidly, landing on everything and nothing all at once. "All jokes aside, it was nice – it was moving – watching you advocate for Kara like that. It… I lost my sister, and it – it was nice."

"Sara," Alex breathed, wondering what else Kara had left out of her stories from the other earth. She held out both hands to Sara's forearms, but the woman stepped back quickly.

"It's fine, I don't want to do a whole thing, I just… I wanted to tell you that it's nice. Kara's lucky to have you, and you're… you're lucky to have her. Cherish it, you know?"

Alex nodded, eyes stinging and throat tight. Sara lifted one side of her mouth into a grimace and held up her glass. "Christmas."

Alex clinked her own glass against Sara's quietly.

"Christmas," she whispered as Sara strode away, leaving Alex to find Kara – dolling out nearly as many cookies as she was putting in her mouth – and pull her into a long, long, long hug.

"No no no, but okay, Back to the Future, you guys gotta have back to the future."

Cisco shifted uncomfortably and Sara thumped Winn on the back as she passed by what she was thinking of as the geek squad. "Sensitive topic, IT guy, might wanna pick another franchise."

"Ah, so you know it's a franchise! So it does exist on your earth!"

"Yes, Winn, Leonardo DiCaprio won all the awards as Marty McFly," Caitlin told him as Felicity swooned slightly.

"Leonardo – what?! Okay, okay, but music: did Beyoncé still drop Lemonade this year?"

Felicity took her glasses off and pinched the bridge of her nose. "Senator Knowles sells drinks here?"

Winn leaned back and positively cackled with delight as Caitlin, Cisco, and Felicity glanced between each other confusedly.

"So hold up, though, I'm still confused – parallel earth trivia can wait – you designed Supergirl's suit without a facility like S.T.A.R. Labs? What kind of twisted sewing polymer genius are you, Winn?"

"Hey! I do all that stuff for Oliver with three computers, wifi, and a keyboard."

Caitlin grinned and slapped Felicity five.

"No one's questioning your badassery, Felicity," Cisco held up a mock-impatient hand and turned to Winn for an explanation.

"Not only did he design Supergirl's suit without a proper lab, but he designed Guardian's suit all on the sly with whatever resources he could scrounge from the DEO," James told them, hopping over the couch to collapse next to Winn and thumping him on the shoulder lightly.

And just like that, Winn gained major tech support credentials on multiple earths.

Sara leaned on the side of the couch, sipping at her eggnog, half-listening to the geek squad babble about some computer program or other. Most of her attention, though, was in the kitchen, on Alex and on Kara and on the way Kara leaned into her when she laughed, on the way Alex kept blushing. It didn't take super hearing to figure out that Kara was teasing Alex about Maggie, and Sara sighed.

Diggle squeezed her shoulder as he passed her on his way to talk to Oliver. "You okay, Sara?" he asked in the same tone he'd used for months with Oliver when they'd all thought she died. Again.

She grunted, not taking her eyes off the Danvers sisters.

"So, you're either checking out Supergirl, checking out Supergirl's badass DEO agent sister, or you're thinking about you and Laurel."

Arms crossed over her chest now, Sara glanced in Digg's direction without actually looking directly at him. "Would it be super fucked up to be doing all three at once?"

Digg chuckled and pulled her into his chest. When they first met, she would have killed him – quite possibly literally – for the intimacy of the gesture. Now, she just sank into him slightly.

"Hey Danvers!" she called, drawing warmth and Christmas spirit out of her cold, soulless memories from her friend's embrace. Both sisters turned to look, faces frozen mid-laugh.

"Kara," she clarified. "Barry tells us you've got some neat parlor tricks up your sleeve. Something about cooking turkey with your face and popping champagne?"

"Oooh!"

J'onn groaned, bemused, and the Superfriends chuckled, shifting so their new friends from the other earth could crowd around a wide-eyed, grinning Kara.

Oliver didn't move from his spot by the hearth, arms crossed over his chest, but his eyes followed Kara sharply, full with more of a smile than anything else on his face or body would suggest, as Kara flared up the oven, made water boil, brought a tray of balls of cookie dough to a sizzle – and the cookies to their sweet-smelling completion – all by squinting at them.

While everyone was ooing and ahhing and "Can you make ice?" "Is that even edible?" and "How amazing must you be at physics to know how much pressure is appropriate to apply?"-ing, Maggie sidled up behind Alex, reaching her arms around her waist.

"Somebody had an intense start to the night," she rose on her tip toes to whisper in her ear.

Alex pulled at Maggie's hands, securing them around her waist, holding their bodies flush against each other.

"It's all good now," she offered by way of excuse for her ruthless temper.

"Oh, I know, babe. But, you know the thing is… Sara said something about…" Maggie leaned up even closer to Alex's ear, nipping at her lower lobe, her actions and Alex's groan lost in the midst of everyone's fascination with Kara's tricks. "… whether you're that aggressive in the bedroom, too."

"Do you want to find out, Detective Sawyer?"

"I think I already know, but I uh… I wouldn't mind getting a refresher course, Agent Danvers."

Before she had her way with Maggie right there on the kitchen counter, Alex tugged her into Kara's bedroom, barely letting the door closed before pushing her up against the back of it.

They froze for a moment, eyes locked in a battle that Alex willingly surrendered, burying her hands in Maggie's hair and letting Maggie yank her hips flush against her body, nipping at her lower lip before swiping her tongue across Maggie's mouth in a way that never failed to make her entire body squirm.

Alex's hands ripped at Maggie's shirt, desperately untucking it so she could feel her skin, so she could trace the contours of her abs and slip her fingers under her bra, so she could make her toss her head back and sigh at the ceiling as Alex brought her lips down to her throat.

"Thank you," Maggie breathed between kisses, between flies unzipping and backing Alex up to the bed, between kicking off her shoes and locking her fingers with Alex's as she held her hand back on the bed.

"For what?" Alex asked, her tongue unrelenting against Maggie's.

Maggie pulled back slightly, looking down at Alex with tousled hair and swollen lips and love written all across her face.

"You're running buddies with all these… superheroes, Alex, you… your circle is made up of people who do the impossible every day, and you're one of them, and you're still… you're still spending your Christmas party with all these incredible people…" She smiled slightly and looked away, shrugging at her own words. "… making out with me, touching me, lo—with me."

"Loving you?" Alex finished for her, reaching up now to smooth the hair out of Maggie's face, to trace her dimples with reverent fingers.

Maggie nodded with a question in her eyes, and Alex answered by leaning up into a slow, sweet, perfect kiss that she never, ever wanted to end.

Everyone was laughing and everyone was shouting, egging on both Barry and Kara, now, as they dashed around the apartment – or, in Kara's case, flew – as they were sent out on increasingly strange tasks – come back with ice cream, come back with pizza, come back with a pizza delivery boy, have a Christmas carol sing-off – to see who could do them faster, who would return quicker, who would belt out Mariah Carey music better.

"You look freaked out, Oliver," Digg told him as both men observed the shenanigans in front of them.

"I am freaked out." Digg chuckled and Oliver glanced at him. "These people, Diggle, this earth… How do they celebrate like this, how do they… Kara lost her entire planet, you know Digg, her whole world, and look at her, she's… I don't even know what she's doing right about now."

"What… what is she doing?" Oliver leaned over to J'onn, who was also standing somewhat off to the side.

"Wait for it," J'onn told him, as it appeared that Kara was just holding a bottle of champagne. When it popped from the sheer pressure of her hands and everyone else roared and passed glasses around, J'onn turned to Oliver.

"You know my planet died, too. My people. Like Kara's. And I… In the hundreds of years I've had to grieve, to mourn, to rage, I never once thought that life could be anything but duty or survival, until I met those girls."

He glanced over at Kara, at Alex, who was now slipping out of the bedroom, her hair mussed and her shirt askew, holding Maggie's hand with a secret smile on her face, desperately trying to blend in with people who weren't just getting it on during the family Christmas party in their little sister's bedroom.

J'onn shook his head and chuckled, and Digg did the same. Oliver just stared, blinking, a look of utter confusion on his face.

"It's unsettling. Watching their joy, realizing that they want you to be part of it. That kind of happiness… takes practice."

Oliver nodded gruffly, eyes keen on Sara as she sidled up to Kara.

"Anything else you can do with those hands, Supergirl?"

Oliver read her lips, and Diggle read her body language, and J'onn read Kara's blush and wide eyes and immediate stammering.

"Sara," Oliver and Diggle exhaled, just as J'onn breathed, "The Danvers girls."

"Hey hey hey, I wanna make a toast!" Winn was calling, tapping a spoon ineffectually on the side of the plastic mug Alex had given him, since you broke the last three grown-up glasses we tried to give you.

"You know two years ago, right now, I didn't have a family."

Kara touched Winn's arm as James smile down at her; Barry pulled Iris into his chest; J'onn looked down so Winn wouldn't see his smile; and Alex smoothed Maggie's hair and kissed her neck.

"Two years ago, I didn't have a family, and I didn't even really have friends." Felicity turned to Sara and gestured her to come stand by her with a small, warm smile. Sara took the invitation with a lump in her throat and a song in her chest.

"And then suddenly it's Christmas, and I'm not alone. Suddenly I have the best friends, the best family, I could ever have asked for. And let's be real, our Christmas party looks like something out of a Doctor Who episode, except, well, travel between parallel universes in Doctor Who threatens to collapse them all, so let's hope Cisco's portals didn't cause a rupture in – "

"Oh my god, you guys have made him worse," Alex groaned with a grin at a beaming Cisco and Caitlin. Even Oliver laughed, and Digg nudged him in the shoulder affectionately.

"No, but seriously, though. It's Christmas, it's Chanukah – " Felicity gave a small whoop and Sara bit her lip. "And I'm surrounded by the best people I could ever imagine knowing, let alone being able to call my family."

Alex left a long kiss on Maggie's cheek and Kara beamed, one hand still on Winn's forearm and the other on James's shoulder.

"We appreciate you, too, Mr. Schott," J'onn called up as Winn swallowed back a tear or two.

"Awwwwww, J'onn!" James, Kara, Alex, and Winn chorused all at once, while Maggie laughed into Alex's arms and the sense of belonging each of them had searched in vein for their entire lives poured through their every vein like Christmas magic.