Kate settles her niece on the soft play mat on the living room rug, her eyes on the girl as she eats. Her knees pulled up onto the couch, she curls against Castle's side and rests her head against his shoulder, still trying to pull herself up out of sleep.

He keeps glancing between her and the baby, his whole face consumed with his smile. Every so often, his jaw hangs slack as he momentarily forgets to chew, and Kate has to keep biting at her lip so as not to laugh at him.

"So, how was work?"

Shaking her head, Kate settles her free hand against his cheek and leans in to kiss him, murmuring against his mouth. "I know what you're doing."

"Who me?" He chuckles, tongue darting out to taste the seam at the corner where her lips meet. "Not doing anything."

"You're trying to not mention any of the things you desperately want to mention."

His cheeks pink, the embarrassment making him look so much an adorable little boy that Kate lets her body fall into him, her arm twining around his waist. Castle buries his mouth against her hair and scatters kisses along the creamy line of her scalp, his own arm curling over her shoulders.

"You're going to be my wife. In three months. And I guess I'm waiting for you to freak out."

"Do you know the first time I thought about being married to you?" She hums. Brooke squirms on the mat, her gums smacking as she starts to whimper, and Kate leans down to gather the girl against her chest.

"At Ryan and Jenny's wedding? When you said third time's the charm, you were thinking about you and me."

It's not a question, his voice pitched low so it rips through her stomach like thunder. Kate turns Brooke around and settles the girl with her legs either side of Kate's thigh, bouncing her knee to keep her entertained while she dusts her mouth to the cleft of Castle's chin.

"No. Well, yeah. I was thinking about us. But that wasn't the first time. During that case with Kyra, she said something to me and it made me think about it. About what it would be like to be your wife."

"What did she say to you?"

Kate grins, kisses him soft and fleeting but still, always, infused with so much tenderness. The words flutter in her chest, where they have been a constant source of hope for four years now, and it feels amazing to finally be able to share them with him.

"She said he's all yours."

"Oh Kate." He draws her in against his chest, his biceps almost crushing her with the ferocity of his hug. "Kate. I've been yours since that first case."

Against her knee, the baby's whole body jolts. She goes totally quiet, and then it happens again. A hiccup. Kate's eyes dart to Castle's face to see the laughter creeping across his mouth and flooding the corners of his eyes. He takes Brooke from her and holds her tight under her arms, bouncing her against his thighs.

"Hi baby girl. Do you have the hiccups?"

Their niece hiccups again, the noise and the jolt of her body making all three of them laugh. Kate presses a kiss to the girl's nose, her forehead, and then shifts up to kiss Castle as well. He grins against her mouth, freeing a hand to cup the back of her head and keep her close.

"That's so cute. You are just so cute, aren't you baby girl?" Kate murmurs, completely giving up on not being a sap. The baby is warm and bubbling with joy and she looks so perfect in Castle's arms that Kate just wants to climb into bed and curl up with both of them, let herself melt against the sheets.

Castle laughs at her, kissing the end of her nose in echo of Kate's own show of affection for her niece. "She's not the only one who's cute, Katie."

"Don't call me that. Especially not when you've been talking all day about getting me pregnant. My dad calls me that."

He snorts so loudly that Brooke startles in his arms, wriggling her way free from his grip in an attempt to turn and look at him. The baby smacks her little fist against Castle's cheek and giggles at his dramatic show of pain, repeating the move again and again until Kate catches her flailing hand and brings it up to her mouth.

"Sorry. Yeah. That's kinda gross, huh?"

"So gross." Kate agrees.

The baby hiccups again, mashing her face into Castle's shirt and giggling against him. It's seriously adorable, the wash of surprise over her face each time her body jerks, the momentary catch of her breath and then the eruption of laughter. Kate tugs her phone free from her pocket and opens the camera application, framing both her fiancé and her niece in the shot.

Castle props her chin against the top of the girl's head and grins at her. And she's so relieved to see that it's a real smile, his most genuine one, and not the one she's so often faced with when she photographs him.

Well, that's not fair. It's not so bad anymore. Not after almost two years of being with him. She's seen him sweet and shy as he falls asleep next to her, intense and passionate when he hovers over her in bed, bubbling with effervescent joy as they walk through the park.

That man, the one from the book jackets and page six, she doesn't see him anymore. If she lets herself think about it, she never really did.

Brooke's mouth opens wide on a yawn and Kate puts her phone away, freeing her hands to scoop the girl up and cradle her in both arms like a newborn. "You ready for sleep, sweetheart?"

"Her and me, both." Castle says, stretching both arms above his head and arching his back. The move reveals an enticing slice of his abdomen, the patch where stomach meets hip like silk. It was one of the first places on his body she ever got to taste, and ever since that first night the meeting of his skin and her mouth feels like coming home.

"Shall I put you both to bed?" Kate smirks, getting up from the couch and raking her fingers through his hair. He grunts at her, standing to his full height so Beckett feels suddenly small against his chest. She never would have guessed, but she loves how his body dwarfs hers, how it makes her feel safe and cherished and always so loved.

"Put Brooke in the crib. And then you and I can reacquaint ourselves with the couch."

An eyebrow creeping up to meet her hairline, Kate's mouth stitches into a seam as she regards him. "The couch? What's wrong with your bed?"

"Nothing. It just creeps me out, the thought of her being in there while we're. . .cuddling."

"Cuddling." Kate scoffs, rolling her eyes at him over her shoulder as she moves for their bedroom. "Castle, she's four months old. She won't get offended if you say the word sex."

She watches the thread of tension in his jaw, how it jumps like an electric current on its way to traverse the rest of his body. "Kate. Put the baby down. Please."

Kate leaves him in the living room and settles Brooke in the bassinet, bending almost in half to kiss the girl's cheek. "Goodnight, baby girl. Sweet dreams."

And then she moves back through to the living room and her fiancé and his mouth.

Eventually, after the hot rush of desire has ebbed from his system and he can breathe again, Rick manages to sit up and take Kate with him. Shirt creased from where he shoved it up to get his mouth on her and her underwear somewhere across the room, she looks so completely delicious that he could go again.

Despite the fact that two minutes ago he was completely sure that his heart was about to just cease functioning in his chest, he could totally go again. Right now.

Instead, he paints her mouth with his own in a chaste kiss and fishes her leggings from the floor, tugging them back up her legs. He pulls on his own sweatpants too and then he lies down again, his spine flush with the back of the couch and Kate curled in the cove of his body.

"Wow. Who knew just practicing would be so intense?"

She laughs at that, full-bodied and without a trace of self-consciousness. "It's always intense with you and me."

"That's true. But this time was especially. . .wow."

"Were you thinking about it?" She rolls onto her back and sets her palm at his cheek, circling her thumb against the cleft of his chin and smiling softly. Serene and gorgeous.

He kisses the smudge of her mouth, snuggling down further into the couch and hiding his grin at Kate's hair when she curls into his chest. "Until you made me stop thinking."

"I was too."

"You know what's fantastic?" Rick smirks, letting his eyes drift closed. They should get up, shower and change, but right now he just wants to relish the languid line of Kate's body next to his, the warmth that floods out from the epicentre of everywhere their skins kiss. "When you have a bump and we get to try tons of new positions."

"You'll still want me when I'm huge?" Kate asks, already half-asleep. Her hand comes up to slide underneath his shirt, two fingers pressed below his ribcage. He's gotten used to the touch now, how the brush of her skin right there feels like her grounding him.

Castle brings his arm tighter around her, his palm spanning the back of her skull to tuck her head underneath his chin. Sometimes, nights like this one when he feels he could burst with love for her and just leak all over the hardwood, he needs to have her close.

"I always want you. And when you're gorgeous and swollen with our child? God, Kate, I can't think of anything sexier."

His eyes closed, he feels the heat that floods into her cheeks against his chest, even with the cotton of his shirt between them. There's a long moment of complete quiet as Kate digests what he's saying, and then she presses a kiss to the fabric over his heart. "I guess I can learn to love your grey hair then."

"Excuse me?" Castle sits bolt upright, struggling his way free from under Kate's body to climb off of the couch and charge for the bathroom, hitting the light switch so ferociously he has to take a second to make sure he hasn't smacked it right off the wall.

So close to the mirror that his nose brushes the glass, Rick inspects his hair at the temples for any hint of grey. And there's nothing. Of course there's nothing. She's just playing with him. But even so, his heart is pounding hard in his chest.

He doesn't turn at the sound of her footsteps, lowering his eyes so as not to accidentally meet hers in the mirror. Kate slides her arms around his waist, her chest pressed to his back, and she arches onto tiptoe to get her mouth at his ear.

"I'm just teasing. You don't have grey hair. But even if you did. . .I wouldn't mind."

"Oh really?" He turns in the circle of her arms, peppering kisses to the arc of her smile. "That does it for you, huh Beckett?"

"You do it for me." She shrugs at him as if it's nothing, but he sees the tremor of insecurity zip down her spine, sees the way she rocks back on her heels as if she needs a little bit of space from him after a confession like that.

"Shit, Kate. God. You can't- I need- the baby." He splutters, his stupid tongue a too-thick and entirely useless thing in his mouth. His teeth also, slamming into each other as if they haven't been working in collaboration for forty five years now. As if the top and bottom rows have never before met and are taking the opportunity to violently introduce themselves.

Kate swats at his chest, pushing him backwards. He follows blindly, too busy trying to get his mouth against hers and pray that at least this, he can do well. Take her apart the same way she does to him.

"The shower. Go. Go." She hisses at him, peeling off her shirt and then her leggings so lightning fast he barely has time to crane his neck in search of a glimpse of her naked skin before she's stepping inside of the shower stall and turning her back on him.

Not that her back is, uh. . .a problem.

"Why am I so tired?" Kate groans, her words trailing off as her jaw cracks wide open on a yawn. She nuzzles her nose into Castle's chest, his arm slung around her shoulders almost haphazardly. It's sweet, the way he tucks her in close against his side.

She feels him stir and realises too late that the rise and fall of his chest next to her has been laboured with sleep for a while now and she probably woke him with her whining. Well, she can't let him sleep on the couch. And this way is kinder than how she would have done it.

"Time s'it?"

"Ten thirty. You ready for bed?" Kate hums, her voice soft and inoffensive. She can't seem to help herself when he's all rumpled with sleep and completely adorable like this, it takes everything she has not to melt entirely.

"You coming too?"

"Yeah." She stands, taking his hand to tug him up with her and pressing a chaste kiss to his cheek. "I'm exhausted. And I haven't even spent all day with a baby."

"No, you haven't. But I thoroughly wore you out." He nudges his head against hers even as she's leading him towards their bedroom, his body a furnace behind her.

God, she loves nights like this. When they're both teetering right on the precipice of sleep, crawling between the sheets and snuggling up to share the blazing heat of his body feels absolutely perfect. Such a blissful relief to finally close her eyes and just rest. With him there at her side.

Kate scissors her legs to get comfortable, inordinately grateful that they already went through their nightly routines before they settled on the couch to watch a movie and now she can just-

Stop holding on.