A/N: Written for the tumblr anon who wanted to know what would happen if Beckett followed Castle to Vegas pre-Limey, married him, and the repercussions that would follow once they returned home.

Set immediately before 4x20, The Limey.

Kate remembers to turn her phone back on once she's in the taxi she hailed at the airport, wincing at the landslide of notifications that fill her screen. Most of them are from Lanie, texts and calls alike, and perhaps sending a text that she was heading to Vegas for the weekend right before boarding the plane wasn't her best idea.

Beckett sighs and tucks the phone back into her pocket, still not sure what the hell she's doing here.

It had been Alexis, of all people, who had contacted her mere hours ago. The girl wasn't happy with her, wasn't exactly thrilled to be speaking with Kate at all, but her concern for her father was greater than her strengthening grudge towards Beckett, the woman who had unknowingly broken his heart.

"I don't know what happened between the two of you, but I can't stand seeing him like this anymore," Alexis had stated as soon as Kate had opened her front door. Alexis hadn't made any move to come in, remaining stiff and aggitated in doorway, her face pinched, her hands in fists at her sides, and steely determination radiating from her tense figure. "All he does now is come home, get drunk, and fall asleep at his desk and I know it's because of you. I don't know what you did or what he did, but one of you needs to grow up and apologize or confront each other or just - whatever. Do whatever you need to do," his daughter had practically pleaded, exasperation in her eyes as Kate had stared back at her, stunned and confused. "If you care about him at all, just tell him or let him go. Just stop hurting him."

Kate had remained frozen in the doorway for a long moment after his daughter had turned on her heel and strode down the hall.

Ever since the bombing case, Castle had been acting strange, cold and distant, and after hearing of the state he was in in his own home, in front of his daughter, there was only one valid reason that came to mind.

He knew.

She had dashed out of her apartment, found Alexis on the street before she could disappear in the crowd, and swore to fix it, offering to make the trip back with her to the loft to meet with him. But Alexis had shaken her head, snagging a notebook from the messenger bag on her shoulder and scribbling down information, his hotel and his room number as she revealed he had gone to Vegas for the weekend to "clear his head".

And that is how Kate Beckett had ended up on the first flight out to sin city.

She has the cab driver drop her off at the hotel he's staying at but doesn't check in, assuring the woman at the front desk she's only come to meet someone.

She finds that someone in the connected casino, a drink in his hand and a blonde on his arm, a picture of the man she had balked at four years ago. She doesn't like that man very much; she wants the one hiding beneath back.

Kate doesn't even hesitate.

"Planning to get lucky, Castle?"

He startles, some of the alcohol in his glass splashing from the tumbler, onto the blonde woman's sparkling dress.

"Ricky," she hisses, stepping back and blotting at her dress with a napkin while Beckett represses a smirk.

But it's easy to bite back a smile when he's glaring at her, the momentary surprise in his eyes fading beneath the surge of irritation, and it hurts her, to witness how much he has changed, what her lie has done to him, to them.

"What are you doing here, Beckett?" he mutters, spitting her name like acid, but Kate steps in closer, between him and the disgruntled blonde still fretting over the mild stain on her party dress.

"Taking a gamble," she shrugs, standing right in front of him. She doesn't fit in here, still in her pantsuit from work, still wearing her heels that elevate her to his eye level. "I need to talk to you."

"You're out of luck," he chuckles, but the sound is dark, hollowed out and free of amusement, but no way did she just fly across the country to be brushed off.

"Rick," she pleads, softer, lifting a hand to his chest when he makes an attempt to walk past her.

"Is this the woman you came here to forget about?" the blonde inquires, poking her head over Kate's shoulder and Beckett bristles, resists the urge to jab her elbow into the other woman's ribs. "The one I was going to help you forget about?"

The sultry tone of the woman's voice has her stiffening, head jerking over her shoulder to glare at the bimbette who shrinks a bit under her narrowed gaze.

"You wanted to forget me?" Kate mumbles, glancing back to him with her heart shredding itself against her ribs as the other woman's words sink in.

Castle lifts his fingers to his eye sockets, pressing down hard, but Kate nudges in closer, eradicating the boundaries of her touch and nudging her knee between his, curling her hands at his wrists and tugging them down.

"If you don't want to remember," he gets out, his voice rough and scratchy, but his eyes sharp and steady. "Then neither do I. Now if you don't mind, Jacinda and I-"

"Jacinda?" she growls, holding tight to his wrists when he looks past her, plastering on a charming smile she's seen in too many newspaper articles.

"Beckett, let me-"

"I remember every second," she snaps, earning the pierce of his gaze, fierce and fighting, but good, she wants to fight. She wants to fight hard for him. "I remember what you said."

"Then why did you lie?" he bites out, demands, and she struggles with the excuses, the instinctive urge to run.

"Because I wasn't ready, because I wanted to be more, because I wanted you and I didn't want to ruin it," she says, finally says it all, and feels the tight knot of panic in her chest, right beneath her scar, begin to loosen as the rage in his eyes starts to recede, the hard lines that she had inadvertently carved into his face softening.

"Wanted me?" he echoes and Beckett nods, letting go of his wrists to glide her hands along his forearms, up to the tense muscles of his biceps.

"Want," she corrects, drifting in all too easily when he places tentative hands at her waist. "I wouldn't have flown out here for anything less."

There are still hints of uncertainty hiding in his eyes, apprehension she yearns to abolish, but most of the anger is gone, the wounded betrayal as well, and her eyes flicker to his mouth-

"Um, Ricky?"

Kate tightens her fingers on his arms, but he slips his hand beneath her blazer, under her blouse, spans his fingers at her lower back, his warm palm heating the base of her spine and sending electricity climbing up her vertebrae.

"Jacinda, I'm sorry, but I just-"

"Oh, no worries, sweetie. I totally understand and really, I'm so happy you two could work things out!" Jacinda beams from behind her, her jovial voice grating on Beckett's nerves. "But you know, I have an entire night left of this layover, so if you're still looking for some fun, maybe all three of us could-"

Was she really…? Oh no, definitely not.

Kate's hands abandon his arms in favor of his face, coiling around his ears and jerking his mouth to hers, claiming his lips in a kiss that shows him and the bimbette at her back exactly what she thinks of that proposition.

He was hers.

She nips hard at his bottom lip, punishes with the bite of her teeth, and soothes with the heat of her tongue when he groans low in his throat, using the hands at her waist to haul her body against his, fitting her tight and close against the hard wall of his chest, the firm muscles of his thighs.

"I don't share," she growls, grinning when his eyes slide open, black and swimming with lust as she releases him to answer the woman still watching them with a raised brow. "So we're going to have to decline."

Kate steals one of Castle's hands from her waist and guides him out of the casino, out into the sea of lights the city has to offer.

The next morning, she wakes in his bed, a brutal headache radiating through her skull while the man at her side radiates heat along her naked skin.

For just a second, her body stiffens in panic, but then slowly, it all comes back, the memories streaming in, abolishing the tension limb by limb until she's relaxed beside him once more. But the nerves don't cease to exist, the uncertainty alive as she withdraws her hand from beneath the bedsheets.

The ring on her left hand shines in the sunlight breaching the curtains he forgot to close.

Kate rolls on her side, finds his left hand with ease, outstretched towards her, and brings the second piece of evidence out to match with hers, twining their fingers and watching the rings clink together in union. They got married last night.

"Kate," he mumbles, face still half mashed into the pillow, and she lowers their tangled hands back to the mattress, reaches with her right to card her fingers through his disheveled hair.

Castle hums at the touch, a gentle smile spreading along his lips before his brow creases and he's squinting an eye open.

"It… wasn't a dream?" he murmurs, blinking a couple of times before pushing up onto his elbows, staring back at her with wide, clear blue eyes despite the hangover she knows he must share.

"No," she chuckles softly, biting her lip as she stares up at him. "You definitely weren't dreaming."

She squeezes his hand and he glances down, lips parting at the sight of the wedding bands.

"We - oh we got married."

"We did," she nods, trying not to laugh at the awed yet panicked expression on his face, trying not to recognize the insecurity that blooms at the latter. "You don't remember that part?"

"I do," he assures her quickly. "I definitely remember, I just - why aren't you freaking out?"

Kate sighs and sits up, allowing the sheet to pool in her lap and flicking his ear when he fails to lift his gaze from her chest.

"You saw it all last night," she huffs as he rises alongside her, his bare chest against her shoulder as he brushes a kiss to her cheek, and oh, she could get used to this.

"And you actually believe that's enough?" he hums in her ear and she buries her grin in her bent knees before he starts something that requires no talking at all.

They need to talk about this; no more sinning by silence for either of them.

"I know we were kind of drunk," she begins, fiddling with her hands, spinning the ring on her finger while she speaks. "And I know it's too soon, that we - that there was a lot we should have done before we took a step like this-"

"Kate, I can get it annulled within the hour if that's what you want," he murmurs, brushing his hand along her shoulder in comfort, reassurance. "We can just… call this a trial run, practice for the real thing."

Her heart flutters at that and she turns her head, rests her cheek on her patella as she meets his eyes, so soft and understanding, ready to act on whatever she decides.

"Planning to marry me again down the line?"

Castle shrugs, circles his thumb at the top of her vertebrae. "If that's what you want."

"You're that sure of me?" she whispers, pulling her knees in tighter against her chest. "Even after… after the whole reason we ended up here."

"You lied," he nods, his face so very serious, contemplative. "And I handled the truth of that wrong, but if anything, this pretty much sealed the deal for me."

Her brow furrowed. "How?"

"I tried to stop, turn off my feelings for you," he admits. "But it was never going to work, and when you flew out here - no one's ever done that sort of thing for me. No one's ever… no one's ever loved me that much," he breathes, casting shy eyes down to his own knees, but Kate curls in closer at his side, presses her lips to his shoulder.

She did love him, so much more than she ever could have known.

"The second I saw you in the casino, it just confirmed it. I was never getting over you whether you wanted me or not." A small smile flickers across his lips, a trace of sadness to it that she immediately wants to eliminate with the newfound privilege of kissing him. "I've loved you for a while, Kate. I'm not saying it will be easy, not all the time, but you… I just want you."

Beckett untangles the sheet from around her waist, tugging it from his as well, and crawls into his lap, embracing this wonderful intimacy that is still so new but so right, and framing his face in her hands, abrading her palms on his stubble and brushing her fingers at the wrinkles extending from his eyes.

"I love you too, Rick," she murmurs, finding beauty in the light that fills his eyes at her words. "And I don't regret a single thing we did last night, so I see no reason for an annulment."

Castle's hands span her lower back, caressing the smooth expanse of skin, the ridge of her spine. "Really?"

Beckett nods, smudges a kiss to his mouth before nudging on his chest, pushing him onto his back.

"Now, time for morning sex with your wife, yeah?"