Based on a prompt by Ali, which is at the end to avoid spoilers.

Many thanks to Andy for the beta and Travis for the cover art.

Set late season 4, somewhere between 4x17 (Once Upon a Crime) and 4x19 (47 Seconds).

The evening is a smashing success.

Alcohol is flowing, bidding for the silent auction is going well, the venue is crowded with people, and Kate looks absolutely gorgeous in her long, sleeveless, purple dress. Her brunette curls are arranged into an elegant updo, eyes darkly lined; she's stunning all the time, but she's impossibly beautiful tonight.

It's something about her eyes, he thinks. They're sparkling with far too many emotions; gratitude, nervousness – she's giving a speech later, he reminds himself – a hint of melancholy, too, invisible to the untrained observer but Castle has no trouble spotting it. But there's something more. Something resembling timid adoration that sparks in her eyes every time their gazes meet.

He doesn't understand it at all, but he's been on the receiving end of it multiple times so far tonight and it makes his heart flutter and stumble about in his chest, threatening to beat out of the cage of his ribs and take flight.

God, he loves her.

Currently, she's across the room chatting with Michael Connelly and nursing the single glass of champagne she's had this evening. Kate catches him watching her and tosses a grin in his direction, that same sparkling tenderness illuminated by the soft lighting of the crystal chandeliers.

He smiles back, feels the happiness tugging the edges of his mouth and crinkling the corners of his eyes. It's not the usual smile he wears when he's in public, but he can't suppress it.

Not for her, and certainly not tonight.

For months, he'd been unsure this fundraiser was ever going to happen, the planning abruptly put on hold following her shooting last May. Even once she was back at the precinct and the bitter sting of their summer apart had begun to fade, he refrained from bringing it up. She was still healing, still struggling with the aftermath of the gunshot; he didn't want to put anything else on her plate, least of all something that hadn't been her idea to begin with. She'd been going along with it during the initial planning stages, but she'd also admitted early on that she wasn't terribly keen on the idea of having to give a speech about her mother.

But she's here and she has a speech prepared and she's walking towards him now with a soft smile and he's just so completely unprepared for the waves of emotion she's eliciting in him tonight. He's used to partially-suppressed smiles and meager glimpses of what lies inside her walls. He's not used to such unbridled openness.

It's not until she's beginning her speech fifteen minutes later that he starts to understand why her eyes have been shimmering specifically for him for the past two hours, why she's been allowing him hints of something beneath the surface that he's never before been privy to.

He can't help but wonder how long she's been planning this revelation.

"Thirteen years ago," Kate begins, adjusting the microphone with one slightly shaking hand, "I spent most of an afternoon standing in line at a bookstore in Midtown, waiting to meet my mom's favorite author so he could sign a copy of his newest novel for her. When I got to the front of the line, I told him my mom's name and explained that it was a gift, and he wrote a quick birthday message for her before he signed his name. I went home and wrapped up the book and hid it away so my mom wouldn't find it."

She takes a deep breath, buys herself some time with a quick sip of champagne.

"Five days later, my mother was killed. She never knew that there was a birthday present hidden in my closet. She never knew that I'd met her favorite author and he'd signed a book for her. She never knew that she wouldn't live to see her birthday."

Kate's voice tremors slightly but she holds it together, shields the sadness behind the glimmering green of her eyes. They're so bright tonight, the purple of her dress somehow bringing out the emerald tone of her irises.

"It was months before I could bring myself to unwrap the book, even longer before I was able to read it and see why she'd always been such a fan," she continues. "But once I started reading, it didn't take long for me to figure out why she loved his novels. My mom spent her career fighting for the little guy, and she worked tirelessly to ensure that justice always prevailed. Just like it did in the book. Just like it does in all of his other novels." Her eyes flit around the room as she speaks, dropping to find her partner's as she continues. "This author, of course, is the organizer of tonight's event: Richard Castle."

Hundreds of eyes turn to him but he barely notices, wholly transfixed by the stunning woman standing at the podium, smiling down at him as though he's the only one in the room. His mother and Alexis have spent the last four years commenting on the utterly smitten way he looks at Kate – "It's like you're wearing your heart in your eyes, Dad," Alexis has said – but he's not used to her gazing at him like this.

"I've spent the last thirteen years of my life working to carry on my mother's legacy," she continues, eyes breaking from his to meander around the ballroom again. "I spend every day fighting for justice and fighting the battles that she never had a chance to win, and I can only hope to make even a fraction of the difference that she did in her time with us. But I can't do it alone. There will always be battles to fight and we'll always be in need of people who are willing to work as tirelessly as she did to ensure that justice prevails. So when Castle suggested the idea of setting up a scholarship in my mother's name to help those who hope to follow a similar path, I realized that he'd come up with the perfect way to honor her memory."

Kate smiles at him again and he's damn glad he's not up on the stage with her because he really doesn't need everyone in the room to see the tears she's bringing to his eyes. For all her nervousness about the speech, for all her earlier statements that she's never been very good with words, she's poised and confident and she's absolutely undoing him right now.

He's so proud of her and he's so in love with her and he really just can't hold it in any longer.

"When I stood in that line thirteen years ago, I never would've fathomed that my mom's favorite author would one day become a part of my life. But I like to think that she's up there laughing at me right now as payback for all the times I made fun of her for being such a fan of Castle's books."

Soft laughter floats around the ballroom and Castle wants to join in but he's pretty sure any sound that leaves his mouth right now will be something between a choke and a sob so he bites it back, forces himself to remain silent.

Kate reaches for her glass, raises it in his direction. "So thank you, Rick, for everything you've done to organize this event and establish the Johanna Beckett Scholarship Fund. And a heartfelt thank you to all of you for coming out tonight to support a cause that's so near and dear to my heart," she concludes with a tentative smile. "I know that my mom would be incredibly touched by your support. Thank you."

The room fills with applause and Castle joins in but he's impatient. She deserves every bit of the praise she's receiving but he really just wants everyone to stop so she'll leave the stage and come down to find him because there are so many things he needs to say to her right now.

But it doesn't work out that way. Of course it doesn't. She's stopped by so many people as she descends from the podium, all wanting to shake her hand and offer their support. Castle promptly finds himself surrounded as well, finds himself receiving praise he's certain he doesn't deserve, so in a great act of self-control he temporarily puts aside his feelings for Kate and engages with the attendees.

After all, he's here tonight as a host. He's here to socialize and schmooze and raise as much money for the scholarship as he possibly can.

For more reasons than he can count, he wants this evening to be an incredible success.

It's nearly forty minutes before he finds her, sipping from a second glass of champagne and gazing unseeingly at the couples swaying on the dance floor. She catches his eye as he approaches, pink lips spreading into a gentle smile.

"Hey, Castle," she breathes as he comes to a stop in front of her.

"Hi," he manages around the emotions clogging his throat, finds his fingers suddenly shaky on the stem of his champagne flute. He wants to hug her, wants to kiss her, wants to talk about her speech, wants… so many things.

"Dance with me?" he asks instead. A compromise, and hopefully a chance for a semi-private conversation.

She nods, sets her glass on the high-top table behind her. "Lead the way."

Kate takes his proffered hand without hesitation, follows him onto the dance floor and settles easily into his embrace. She can feel the warmth of his palm on her lower back, feels his fingers spread wide even through the fabric of her dress. His embrace is soft but firm, as though he's afraid she might slip away, but she has no intention of running from this tonight.

From him, from them.

He put together a fundraiser in honor of her mother because he loves her, and she's been working so hard in therapy to get to the point where she can wholly love him back. She's not quite sure she's ready to say the words, but she knows she's ready to show him.

After what he's done for her tonight, she wants him to know.

"Your speech was wonderful, Kate," he murmurs as they begin to sway, one hand cradled in his, her left curving around the arc of his shoulder.

She dips her chin, eyelashes fluttering shyly, but her hair is pulled up, doesn't provide its usual curtain to hide the blush that stains her cheeks. "Yeah, well," she answers softly, still not quite meeting his eyes. "I thought you deserved to know the truth."

"I never knew your mom read my books," Castle whispers.

"Yeah," Kate replies, eyes finally flickering up to find his. "She loved them so much."

"Well she had excellent taste," he offers with a teasing grin, inserting some levity into their conversation.

Kate rolls her eyes but can't help the smile that escapes the confines of her lips no matter how adamantly she presses them together.

"You're my favorite author too, you know," she confesses bashfully as they settle back into the rhythm of the smooth jazz that floats through the speakers. He surmised long ago that she was a fan, that she'd read his books, but she's never confirmed it. Not until now.

She's never particularly felt like stroking his ego.

But he's not in an egotistical mood tonight.

"Reading your books was, I don't know…" she trails off with a shrug, eyes fixed on some point beyond his left shoulder. "Comforting, I guess. I was reading the same words my mom had read. But then it became more about the fact that I was immersed in a world where justice was always found. I think I needed that fantasy since I didn't have it in real life."

Castle doesn't speak right away, merely brings their joined hands in to rest against his chest, all but eradicating the modicum of space between them as they sway to the melodic tune of the saxophone.

"I'm glad my words could help," he finally utters, the statement little more than a hoarse whisper leaving his throat.

Kate slips her hand from his shoulder to the back of his neck, begins toying with the soft strands of his hair that brush against her fingertips.

Castle tightens his embrace in response, curling his fingers around the soft curve of her waist. She leans in, her temple coming to rest against his, and closes her eyes, basking in the glorious proximity.

They sway in silence for the remainder of the song, and not until the music transitions into the next melody do either of them dare break the spell.

"Castle, thank you," Kate whispers, her nose brushing his ear, breath fanning across his neck and raising a trail of goosebumps. "For putting this together. It means the world to me." Her entire body feels shaky and she inhales an uneven breath, hoping to regain some sense of control; but her heart seems to have taken over, blocking out all rational thought and leaving her stripped down and bare. "You mean the world to me."

Castle inhales sharply, arm tightening around her back as he registers her confession. She asked him to wait, to give her time to heal, and he's more than happy to continue doing so if it's what she needs. But her eyes and her words tonight suggest that perhaps the waiting is over.

Hope flutters in his chest, excitement buzzing through his veins, love clogging his voice, and oh, right. He should probably say something.

"Kate," he manages, a choked rendition of her name. But he can't manage anything more. His heart is lodged in his throat and his eyes are threatening to spill over with tears once again and it's taking every remaining ounce of restraint to not blurt out the four words that she doesn't remember but that he so desperately wants her to hear.

She's looking at him like she might be able to handle the admission, but he doesn't want to push. Not tonight. Not when she's already emotionally delicate with memories of her mother.

"You know, there's a balcony around the back," Castle finally says. "Want to get some air?"

Air. He definitely needs some air. She's so close and his senses are infiltrated with her and he can't even think anymore.

He didn't know it was possible to be this in love with someone.

"Sounds good," Kate replies, and oh, thank god.

He must stare at her for a moment too long because she's raising an eyebrow and quirking her lips, and why are they still standing here when there's a hopefully empty balcony waiting for them?

He really needs to pull it together.

Castle loosens his grip on her hand but she doesn't pull away, instead lacing her fingers through the slots between his and allowing them to dangle loosely between their bodies as he leads her from the dance floor. The back of her hand brushes against the fabric of his slacks, black pants that sit enticingly low on his hips. He's discarded his jacket, leaving him in a white shirt and black bow tie; she's always begrudgingly found him attractive but he looks especially handsome tonight.

Then again, he always looks handsome when he gazes at her with so much love in his eyes.

"It's down the back hallway and to the left," he murmurs with a nod in that direction. "I'll meet you there in a couple minutes."

She nods, reluctantly disentangling her fingers from his before stepping back and quietly making her way off the dance floor and around to the back of the room. She tosses a glance over her shoulder, finds Castle watching her but also watching everyone else, assessing their reactions. She furrows her brow but then from across the room a camera flashes, capturing a moment on the dance floor, and she realizes what he's doing.

Making sure no one notices them. Making sure they'll be alone.

Kate is secretly grateful for his discretion because she really wants to kiss him, but she doesn't necessarily want any witnesses to the private moment that's about to unfold.

Although, from the way he was gazing at her while she was on stage, she's fairly certain every guest has done the math. Castle isn't exactly subtle with his facial expressions. He's been practically exuding his love for her since the moment he laid eyes on her three hours ago.

The butterflies have been beating a constant rhythm in her stomach all evening as a result.

Kate makes her way down the hall, easily finds the door to the balcony and slips out into the night. They're a few floors up, high enough that she has a view up and down Hudson Street, can see the lights of One World Trade Center rising far above the city skyline in the distance. Down below, the cacophony of Manhattan echoes through the streets, horns honking, engines revving, the traffic noise a constant in this city.

But up here, with a couple small tables, a few decorative plants, and strings of globe lights crisscrossed overhead, she hears none of it.

Then again, the pounding of her heart is drowning out most of the other sounds.

She's leaning against the railing, gazing out over the New York night when he appears, champagne flute in either hand, jacket draped over one arm, and a soft twinkle in his eyes. Kate smiles over her shoulder, turning to greet him as he approaches.

"For you," he offers, extending one glass and setting the other aside.

Kate takes it from him slowly, fingers lingering against his, and sparks radiate through her arm at the contact.

"And also for you," he murmurs, voice low and deep as he spreads open his jacket, drapes it over her shoulders.

"Thanks," she whispers, can't manage to insert any more volume into her voice. There doesn't seem to be any air left in her lungs.

Castle offers a smile, retrieves his glass. "A toast," he proposes.

Kate mimics him, raising her glass; whatever words he's about to say, she's sure they'll be beautiful. Everything about tonight has been.

"To Johanna," he recites reverently. Beautifully. "And to her extraordinary daughter."

She clinks her glass against his before taking a sip of the bubbly liquid, hoping he doesn't notice how badly her hands are shaking, how unsteady she feels.

Kate turns back towards the balcony, resting her free hand on the railing to ground herself as she stares out over the twinkling cityscape. Castle steps up next to her, close enough that he can rest a hand on her lower back; she falters slightly as she sips her champagne, recovers in what she hopes is a graceful fashion.

If he notices, he doesn't call her out, merely raises his own flute to his lips and takes a sip.

Almost before she realizes what she's doing, Kate leans into him, resting her head on his shoulder. She feels him tense in surprise before relaxing, wrapping his arm further around her waist. Even through the fabric of his jacket, she can feel the gentle dance of his fingers as they trace the curve of her waist, the edge of her hip bone.

"It's so beautiful up here," Kate breathes as a gentle breeze sweeps through, causing the overhead lights to sway, sending the shadows dancing around them.

"Mmm, yeah," he agrees, fingers curling into her waist. "I love this place."

"Me too," she whispers, lifting her head to take a long, slow sip of champagne.

Another light puff of wind swishes through, ruffling Castle's bangs and displacing a few loose pieces of her hair. One strand comes to rest in her eyelashes, sticking to her mascara; before she can react, Castle sets aside his champagne, extends a finger and gently teases it from her lashes, tucks it back into place, and heat floods her cheeks in the aftermath of his touch.

"Have I mentioned how amazing you look tonight?" he murmurs, softly trailing the back of his knuckle over the ridge of her cheekbone before allowing his hand to fall away.

"You're not so bad yourself, Rick," she utters in reply, a near echo of her words from almost a year ago. Only then she'd been in a hotel room on the other side of the country, with a boyfriend and a heart heavy with Royce's betrayal, so she'd retreated to her room before she did something she was sure to regret.

But tonight there's no one else, and certainly no regrets.

Castle is still holding her gaze, eyes intense, so dark, and in them she can read everything, his heart on display. She's frozen in place, entranced by the look in his eyes and immobilized by the nervousness and anticipation. Opening her heart, letting him in… she's certain of her decision, but it's taking all the courage she has.

"Kate," he whispers, so softly she barely hears it. But it's enough to break the moment, reeling her back from the edges of terror to find him close, so close.

She leans in then, closing the remaining distance between them and pressing her lips to his in a tender, lingering kiss.

They separate after a long moment, but not by much, two shaky exhales released in synchronicity as Castle rests his forehead against hers. He turns to fully face her and loop his other arm around her lower back. It's only then that she becomes aware of her arm, awkwardly hanging between them, because they don't normally do this so where in the hell is she supposed to put it?

She settles for spreading her palm wide against his sternum, where she can feel the shaky rise and fall of his chest and the rapid cadence of his heartbeat. Castle tugs her closer in response, tilts his chin to capture her lips once more. His mouth is soft, pliant beneath hers, the kiss gentle, and she feels herself smiling into it, lips curving of their own volition. It draws a grin from Castle, too, and the kiss falls apart around their radiant smiles.

It's Castle who pulls away first, lifting a hand to cup her cheek; she leans into his touch, feels her smile widen as he grins back at her. She's seen him smile for photographs, seen him smile in public, but she's only ever seen him smile like this in private. Eyes crinkling, lips parted, slightly lopsided but completely adorable.

It's quite possibly her favorite sight in the world.

"Hey," he whispers shyly.

"Hi," she replies, finds herself completely giddy with it all, as though they're teenagers sharing a forbidden first kiss rather than grown adults who are already completely in love with each other.

Kate sets her champagne on the railing next to his, freeing both arms to slide around his neck, holding him close as she kisses him again. He tugs at her lower lip, tongue coming out to soothe it, and she parts her lips, welcoming him inside. At some point, Castle's hands migrate beneath his jacket to span her back through only the thin fabric of her dress; the jacket slips from her shoulders, falls to the ground in a heap, but neither is willing to break the kiss to pick it up. Rather, Castle's hands slide south, cupping her ass and tugging her infinitely closer until she's pressed flush against him and can feel exactly how much this is beginning to affect him.

"Castle," she manages between kisses, because they really need to stop before they both completely lose the ability to do so.

He hums against her lips in response, captures them in another deep kiss.

Kate plants her hands on his chest, pushing back slightly, reluctantly. "Rick."

"Huh?" he asks as they separate, completely dazed.

She cards her fingers through his hair, stopping to toy with his ear before allowing her hand to fall back to his chest as she speaks. "We should probably go back to the party."

She'd gladly stay here all night but anyone who notices their extended absence is liable to become suspicious, perhaps head off in search of them. And as much as she wants to be in his arms right now, she really doesn't want anyone to walk through the door and find her in his arms, with her tongue in his mouth and his hands on her ass.

Castle huffs a dramatic sigh, offers a "probably" in agreement followed by an adorable pout, and when exactly did she decide his pouts were adorable?

Kate smooths down his collar, straightens his bow tie before dropping her hands, taking a step back to reintroduce an appropriate amount of space between them. They should probably walk back in separately, too. Just to be safe. She'll go first, because he quite clearly needs a couple minutes.

She's about to turn for the door when Castle's hand snags her wrist, drawing her back. "Come home with me tonight."

She lifts surprised eyes to his, finds him regarding her expectantly.

"We need to get back in there," she reiterates, sees his face fall in the space between her words. "But don't leave without me, 'kay?"

The disappointment vanishes in an instant, replaced by pure joy. His lips curve into a grin once more – the one she loves so much – and his entire body is practically bouncing with excitement and anticipation as he reels her in for a kiss that has her toes curling, leaving her desperate for more.

"I'll be waiting, Detective."

END

Prompt: At the fundraiser, Kate says in her speech that she stood in line & tells him what his books meant to her. Then they discuss on the dance floor.