He stops writing on the murder board, not because she asked him, but because every time he so much as glances at the thing he sees Kate lying naked on her bed, her pale skin and expectant eyes glowing in the darkness.
It helps. At first.
But there are always moments when he turns and finds her watching him, and he immediately knows. It's not obvious to anyone but him - at least, he hopes not - because she's got a pretty great poker face still; it's an imperceptible something in her eyes, a touch of softness where before there was only steel.
The faintest lift to the line of her mouth.
It takes so little to unmake him.
He tells himself Not at the precinct, not at the precinct, forces his hands to uncurl in his pockets, breathes deep and looks away.
But then there's this day when an arrest nearly goes wrong, where a bullet ricochets on the wall, so close, just so close to Kate's head, and his heart stops, paralyzed with anguish and what ifs scenarios.
The vest only protects her chest. The vest only protects her heart and lungs and what if, what if that bullet had been aimed a little better, what if-
He clenches his teeth and keeps it together, although he knows his face must be bloodless, and the only thing he can hear is the wild pound of blood in his ears. Kate has it under control, every inch of her so completely Beckett that she doesn't even flinch before she chases down their suspect - least he can do is not make a scene.
He manages to do that through the actual arrest; he holds himself back as Esposito snaps the cuffs around the bastard's wrists, stays quiet while Kate drives them back to the 12th.
Following her directives, isn't he? For what must be the first time ever. Staying back, making himself scarce.
She doesn't seem as appreciative as he'd have hoped.
He watches her hands on the wheel, the firm set of her fingers, the skin that he knows to be so soft; it's enough to keep his mind settled for now, keep him from continuously going over what didn't happen, what might've happened.
Esposito and Ryan take the last free parking space outside the precinct, so Kate has to park the Crown Vic in the underground garage. Castle is grateful for it, those few minutes they get to themselves - thank god the boys took the suspect with them.
Esposito must have seen the murderous looks Castle was throwing the man.
Beckett turns off the engine and slides out of the car, her brush with death obviously not impairing her natural grace, and he can only scramble after her.
"Kate-"
She must hear something in his voice, or maybe she's feeling it too, maybe she's just better at covering it up, because suddenly she spins on her heels and it's all there on her face, everything his heart's been struggling with for the last forty minutes.
She swallows, her hands curling over thin air as if she's keeping herself from reaching for him, but her fingers won't listen.
"Not here," she murmurs, glancing around at hypothetical witnesses.
She gives a sharp little jerk of her head and then he's following her up the stairs, into a corridor, into a storage closet, quickening his pace to keep up with her. His heart is a trembling thing in his throat, threatens to spill out every time he breathes too deep.
Kate closes the door behind them. He can see her hands tremble as she flips the lock; when she turns to him her face is pale and calm, and her eyes are drowning.
She crashes into him, her nose buried against his neck, her arms tight cords around his chest. The haunting fragrance of her hair surrounds him, soothes him, swallows him whole; he will never tell her she's squeezing too tight.
She takes broken breaths at his collarbone, and he cannot help but wonder which one is real. Who's the real Kate? The woman at the scene who did what she had to do, didn't spare so much as a glance to him, only asked if he was okay before she went after the man with the gun? Or this one, the slim figure who shakes in his arms, who sounds like she's suffocating under the weight of it all?
It's a silly thought, of course. If he wasn't so confused himself, so terrified at the idea of losing her, he'd recognize this for what it is, her formidable faculty to compartmentalize, to keep the Kate out of her Beckett persona.
He'd realize he's screwing it up for her right now.
But he can't. He's selfish, and he's scared, and he needs her badly, needs this. Her body so close that he can feel all her angles and planes meeting his, the brush of her mouth at his jaw, the reassuring smell that tells him she's alive.
"Kate," he whispers again, because it's the only thing that will come out of his mouth. Her name, a plea, a prayer, a promise - all at once.
Her eyes lift to him, glittering diamonds under her eyelashes. Her breathing is easier now, like she's gathering herself, going to sever their connection; he can't let her do that. He needs more, he needs-
His mouth is on hers before he can finish that thought, hard and relentless, taking what she will not give. She resists for a second, maybe two, before the barrier of her lips breaks open for him; she hums his name around his tongue, her body fluid, pliant against his.
He pushes her into the shelves, helps her hoist her ass onto an empty one. Her hips rock frenetically into his, her mouth open, her hands clawing at his sides; he fumbles with her shirt, gives up, focuses on the buttons of her jeans instead.
Buttons, seriously? Who even puts buttons on jeans anymore? Isn't there like a law or something, requiring it to be a zipper?
And when, oh when did his fingers get so fat-
"Hurry," she pants in his ear, so not helping. "Castle, oh please, oh..."
Fuck, fuck, she cannot make these kinds of noises if she wants him to get into her pants. He grunts in relief when the first button gives under his hands, the second one quick to follow after that, and oh, hey, look at that - he's in.
He slips his fingers against her panties, feels the irresistible throb of her, the heat that radiates; he curls his middle finger inside, teases her roughly.
She arches off the shelf, her hips sharply rising into his, a growl vibrating on her lips.
"Castle, no," she begs, but even as she does her body's undulating at his fingertips, craving for more. "No - don't - oh - I don't, oh, you please-"
Shit, he loves it when she's incoherent.
But he knows she has a point - they're in a freaking supply closet, in the damn precinct, and no matter how much he wants to take his time with her, the faster they're out of here, the better.
So he reaches down for his own zipper - he was smart enough in his own choice of pants, thank you very much - impatiently pushes said pants off his hips, as far as they will go, anyway. Far enough.
Kate has dropped her legs from his waist to make it easier for him, is struggling with her fitted jeans when he looks back at her; he helps as much as he can, yanks the fabric down before gathering her up again.
Her mouth is dark red, lovely and ripe - opens so easily under his. He swallows her breath, slips a hand under her shirt, savors the tight curve of her body around him.
"Castle," she urges, biting at his lip, hand fisting at his bicep.
He grins and presses into her, slowly, reclaims her from the danger, the death, everything her job is. You're mine, he says with each thrust, and from the desperate way she grips him, the sounds she makes, she doesn't seem to mind.
He knows sometimes she likes it rough, so he pushes, curious to see just how much she can take; he has her teetering at the edge in no time, so hot and tight against him. He slows down just because he wants to see that look on her face, her knitted brow when she's so close, and right when he sinks back into her, the door shakes behind them.
Her eyes snap open, wide and dark and scared, but her body's already contracting around his, nothing she can do to stop it - she comes, her lips parted around sounds she won't let out, and the way she tries to hold still, the contrast between her furiously working inner muscles and her taut, shivering skin - it might be the hottest thing he's ever seen.
It does him in, sucks his pleasure right out of him, and he has to bow over her and bite at her clothed shoulder to quiet his own release, some of those raw sobs coming out anyway as his pelvis jerks into hers.
"Is someone in there?" a feminine voice asks from the corridor, having obviously failed to pull the door open.
He holds his breath, his cheeks brushing Kate's, feels her mirroring effort not to be heard. Holy shit, they're so screwed-
"Hello?" the voice insists, not someone he knows, he thinks. The doorknob protests when the person tries to turn it again.
He feels Kate's fingers at his neck, her light touch against his sweat-soaked skin. It seems absurd in such a terrible situation, and yet it still somehow manages to ease his heart.
There's a loud sigh on the other side of the door, some muttered cursing that he can only hear snippets of.
"Hey, Charlie!" the voice suddenly calls.
Oh, damn, damn. Just go away, people.
A male voice answers, the words muffled, incomprehensible.
"You have any idea why this stupid door is locked?"
The doorknob gets manhandled once again, but thank god, thank god, it doesn't yield.
"Shouldn't be," the man says. "Maybe one of the cleaning ladies made a mistake."
"Great," the woman says, heavy on sarcasm. "And now how am I supposed to get my staples? Does anyone even have the key to this room?"
"Surely someone has them. Captain must have all the keys to the place, don't ya think? I can go ask him, if you want."
"And what, I'll wait here? That's stupid. You go back to work; I'll ask him."
Their footsteps move away, vanishing in the distance; Castle sucks in a breath, cannot believe their luck.
"What floor are we on?" he murmurs in Kate's ear, not daring to move until all sound has receded.
"Vice," she answers in the same way, her hand slipping off his neck. "Come on, let me go. We don't have much time."
He pushes himself off the shelf and out of her; her eyes flutter shut at the intimate contact and a moan falls from her mouth, body shivering around his.
He quickly straightens out, feels a blush burn at his neck as he zips his pants back up. When he turns Kate is attempting to make herself look presentable, her eyes heated on his, and it would maybe be okay if her hair didn't scream sex so very, very loudly.
"Castle," she murmurs, her voice urgent, her fingers waving from him to the door. "Let's get out of here. You first."
Great. Okay. Okay.
He takes a deep breath, curls his hand around the knob, and turns it carefully. Oh, he forgot to unlock the door. He flips the bolt, hears Kate's impatient sigh at his back, cracks the door open.
The corridor seems clear.
He slips out as discreetly as he can, walks calmly to the stairs, his shoulders slumping with relief when he's safely hidden behind the swing door. Kate joins him seconds later, her mouth pursed and her body stiff with tension.
"Don't stay here," she orders quietly, starts moving up the stairs.
He follows her, his heart still pounding, and not in a good way.
Shit, what would've happened if those people had managed to open the door? If the woman had kept guard in front of the room while her co-worker went and asked Gates for the key?
Oh, man.
No more of this, he tells himself sternly, his eyes on Kate's taut back as he climbs the steps after her. This is her job, the job she excels at, the job she's respected and admired for.
He's the biggest asshole on the planet if he ruins it for her.