A year he's spent imagining this. His writer's mind has come up with a hundred ways it might happen. From the cloyingly romantic notions of winning her heart with flowers and gestures of affection like some awkward teenage imitation of courtly love, to the dark fantasies of carnality and use, disgusting and degrading to both, and everything in between. Nothing – nothing – he could have imagined has come close to this.

The gift she's chosen to give him tonight is infinitely delicate and lovely. Her trust. Her vulnerability. He'll not take advantage of that. He will not fail.

Kate's back to stroking her inner thigh, the bony protrusions of her knuckles just grazing the neon white skin there. Her other hand reaches for his, and he looks to her eyes, asking permission despite the invitation. Her answer comes in the slip of her hand over his palm, the lace of her fingers through his as she guides them to her breast. Castle's eyes flutter closed for a moment, a soft groan escaping on an exhale.

"Watch me," she instructs, and his eyes open as if their lashed lids were attached to blind pulleys, as if her word has complete power over him. Maybe it does. Maybe it always has.

At first, he doesn't know where to look. The hand between her thighs creeps higher, caressing the lambsoft skin where her thigh creases to her pelvis. Her eyes, however – he never thought he'd have Kate Beckett touching herself for him and only be able to focus on her face.

"I wish these were your fingers..." she sighs, parting her folds. His eyes flicker downward. God, she's wet, so perfect and pink and he wishes it was him touching her, too, but...

"What would you want me to do?" Castle asks. He won't break his promise, won't give in just yet, but this is the next best thing. "What do you imagine when you think about this?"

Two fingers plunge inside her and still. Her head jerks backward, eyes closing and her mouth gaping slightly open.

She hesitates, teeth worrying her bottom lip in a way that shouldn't be that enticing. "I... I think about you..." she stammers out at last, suddenly shy and self-conscious.

"Do you want to stop, Kate?" he asks, and he's more surprised to find he genuinely means his concern, that he can think of nothing worse in this moment than her being uncomfortable or feeling pushed. "We don't have to..."

Kate shakes her head, her vigorous denial bringing a bit of ease back into him. "I want to... I just- I've never done... this for a man before. I didn't think... I thought you'd jump at the opportunity..."

Castle nods, dropping a kiss to her damp hair and shifting so that their naked hips touch again. "I thought I would, too," he admits with a hint of his normal humor, "It's a private thing, isn't it?"

"Yeah..." stroking her velvety outer lips with her fingertips, she resumes her attentions, just enough to tease herself, still shy. "I'm a little embarrassed..."

"You're absolutely gorgeous, Kate," he assures her, nuzzling the stony ridge of her jaw with his nose when inspiration strikes, "do you ever think about me doing this?"

She answers instantly. "Yes. Those scenes in Heat Wave obviously weren't written with your pants on. I pictured you in your office..." she trails off, and Castle smirks at how very rightly she's got him figured out.

"Does it embarrass you, to think about me doing this, then? That I think about you?"

"No. It's... it turns me on to think of you, thinking about me. But you're a man." As if it's just expected for him, and her pleasure has to be a shameful secret? He'll not have that.

Castle laughs, a breathless low sound from deep in his chest. "It makes no difference, Kate. What feels good feels good. Watching you touch yourself for me is a dream – and many, many daydreams – come true." She exhales beside him, a relieved laugh on the end of it, and she nods at last, her comfort and confidence returning. "So, you think about me?"

Her free hand smacks his bicep the way it often does when they're bickering playfully in front of the murder board, and the unexpected delight that they're still them even when they're doing this swells in his chest, a word he's not ready to acknowledge bubbling in his throat.

"I do."

Castle swallows thickly, stamping down the echoes of her affirmation his wildfire imagination manages to twist into a very different scenario. Shaking his head clear, he snickers, his hand wrapping lightly around his cock, not willing to further it yet.

"That's a good start. I'd be worried if you were telling me you thought about Esposito while we're doing this."

Giving a startled bark of a laugh, Kate smiles at him, her eyes opening and her shyness staved off. "Gross, Castle," she breaths, her fingers retreating from her body only to smear her slickness around, then returning slowly inside her. He watches her scissor them inside her. "If you were trying to buy a little more time here, that did it."

That wasn't precisely his goal, but she's not wrong, and more importantly, she's relaxed again, her fire back in force.

"I imagined you doing this," Beckett begins, smoke and sex creeping back into her lilted voice as she gains confidence again, "two of my fingers. One of yours."

"Good," Castle prods, rotating his palm loosely and shuddering when he follows her eyes to the movement of his hand, "tell me the story, Kate."

Kate lets out a melodious sound, something between a whimper and a sigh. Her thumb brushes her clit just once and the muscles in her abdomen jump. Fuck, she's close – already? He watches with fascination when she hovers her thumb again, but quickly abandons the bundle of nerves, already oversensitized.

"That- that day with Sorenson," Castle frowns. He does NOT want to hear about that. Isn't there a rule about mentioning exes in bed? "You were so jealous. So fired up. He kissed me and all I could think about was if it was you-" she sighs, "after you admitted to me that morning that you fantasized about me, that is."

"I did not!" He did, actually. But he can tell she's a little embarrassed, wondering whether this was a good idea, and bickering brings them back to a small semblance of normal, of putting her back in power.

"Did so-oh..." she tries to argue between gasps drawn by her lithe fingers. She dips into her wetness again, smearing it around her clit and drawing her lip between her teeth. Castle gives his hand a forceful jerk, twisting his sensitive foreskin over his shaft, the hand kneading her breast abandoning it for her face. His palm dwarfs her exquisite features, "you thought you played it so cool, when you caught us."

"I wanted to rip his head off," Castle confirms, flickering his eyes between the wet thrust of her digits into her own body – wishing to god they were his, but, no, there's good reason they're not doing that tonight – and watching her eyelids flutter at half-mast. He's taken most by the fascinating way her full, pink lips tremble like morning petals in the corners. The little noises she's making without seeming to notice it, on every breath between her increasingly disjointed words.

"God, Castle – I thought about telling him to go. That night, when that little girl was missing, I had to think of something – I thought about you. I thought about asking you home, stress relief, to feel something," Castle stops a moment, his rough strokes on his cock slowing. It's all too much like what's happening now, "I thought you were the only person on that case who felt worse than I did, the only person who understood, I wanted to go to you- I thought about you pushing me against the breakroom counter."

He groans at the visual. It's not a fantasy that exists solely in her mind. His hand resumes its pace, rough but not quite frantic, and the callused pad of his thumb brushes her sculpted cheekbone, urging her to look at him again.

"What did you want me to do?" he begs her raggedly. He needs the end, his mind craves it as much as his body craves release.

"I wanted you to push me against the counter and kiss me," Kate pants, her cheek feeling hot beneath his palm and the primal scent of her arousal flooding the air when she shifts, splaying her legs wider and plunging in and out, in and out. Transfixed, he gazes at the way he can see the muscles in the back of her hand and wrist flex, curling her fingers inside on every thrust, her thumb rubbing firey circles around her swollen clit now. Her words spill out now, practically a series of pleasured sobs, "Oh Castle, I wanted you to touch me, just like this, wanted your hands all over me, I wanted to be yours then, god, I'd had fantasies before... but that was when..."

What? What? He never finds out (and maybe it's better he doesn't, tonight), because suddenly there's no more words. Just a relieved, midnight cry of ecstasy and fullness and thoughtless release that he swallows into his mouth sealed over hers as he explodes, too enthralled by seeing and feeling and hearing Kate fall apart for him, admitting her most private fantasies for him. And only him.

Post-orgasmic Kate is beautifully unbeautiful. Blood pools in her cheeks, blotchy and flamed, turning pink and spreading all the way to her heaving chest. Her hair clings to the side of her face, messy and wild.

Her cooling, still-naked body pressing to his own, he's keenly aware of her thigh hooking over his, brushing innocent against his spent cock, the slick vee between her legs grazing against his hip, the first touch of their most intimate spaces. Her cheek resting on his shoulder. Her arousal-dampened fingers carding through his hair. The glow of her teeth in the dark when she smiles for him, the positively guileless giggle when he can't contain himself and kisses the tip of her nose.

He can't fucking breathe. She's gorgeous and undone and extraordinary and he can't help but think she's everything. But then, he knew that. He wouldn't be here if he didn't, but it'll take some time before he can deal with that.

Until he can, he has this.

There's the way she weasels into his embrace further and cuddles him shamelessly – not a behavior he'd ever have associated with her. But nothing else she's shown him tonight was expected either. There's the way world goes quiet for a while, reduced to her tender touches and his quest to kiss every inch of skin on her face.

There's her hesitant question, muffled by the skin of his shoulder, of whether they can do this again, whether he wants her again, and his whispered promise that they can, his assurance that he does. But only if she lets him take her to dinner before they debrief each other again. There's the roll of her eyes he senses rather than sees and her hum of agreement when she's too tired to respond properly and she's drifting to sleep, not entirely at peace but unburdened enough at least to rest.

There's the crisp weight of a light cotton blanket he pulls over them before he resumes his sleepless shift of watching and listening for what lurks in the shadows and still looms over them.

For now, there's just this and what they've done. And that's enough.

Better late than never, yeah?

Please tell me what you think. I'll make no promises, but there may be a sequel of what happens after the events of "Boom." If you're good...