A/N: For the wonderful Alex, who was kind enough to share some brilliant ideas for a fic revolving around this episode with me. I truly hope that you enjoy this one!

This is all Castle's fault, as usual, turning their murder case into a stupid bet, one where she might have to shave her head if they lose. Unbelievable. And where is he anyway? It's past nine and he never shows up this late, let alone when a case has him hooked, and, in this scenario, his hair and masculinity are both on the line.

Beckett slows her pacing in front of the murder board and fishes her phone from the pocket of her leather jacket, dials his number with hard stabs of her thumb to the buttons. She chews on her bottom lip as it rings, drifts towards the elevator in the relatively scarce bullpen, still milling with a handful of officers, but not nearly as hectic as it had been recently. At least she could feel relief about that.

"Hey," Castle answers, breathless. "I'm sorry, I'm on my way."

"Where have you been?" she hisses. "Ryan and Esposito just left to go check out a lead."

"Oh no," he whines, the muffled blare of a car horn disappearing, the sounds of the city with it, and a chime of elevator doors echoing through the phone. "I was busy apologizing to Alexis for the male race. How long ago did they leave?"

"Maybe half an hour," she sighs, coming to a halt in front of the lift. "Where are you now?"

"I'm in the elevator right… now," Castle finishes, lowering the phone from his ear as the doors part to reveal his anxious expression. "What about us? No break?"

"No," she huffs, turning on her heel and striding back towards her desk, the useless murder board she's been staring at for two hours straight.

"How long have you been here, Beckett?" he inquires from behind her, peering at the board that hasn't changed since he was here last night, glancing down to the empty cup of coffee on her desk. "Hey, don't let this stress you out, we'll-"

"Castle, we are going nowhere on this case while the competition is hot on the trail of a lead as we speak and I am not shaving my head-"

"Okay, okay," he placates, lifting supplicating hands in hopes of calming her. "You will not shave your head, don't worry."

Beckett scoffs and reaches for one of the Expo markers on the board, itching to write more facts, a new theory, something, but when she places the tip of the black marker to the whiteboard, the color stains grey and fading.

"This is all your fault," she mutters, tossing the marker into the trash and striding for the hallway on the opposite side of the floor, listening to Castle stumble after her with a huff of indignation. "Betting on murder cases, ringing the whole precinct into it."

"Hey," he interjects from her back, trotting after her down the empty hallway, towards the seldom-used supply closet where she knows a new pack of markers sits on the middle shelf. "Excuse me if I'm wrong, but I don't recall anyone forcing you to take part in this."

"Peer pressure," she replies, stepping inside the cramped room, a sliver of tension coiling around her spine when she feels Castle follow her in. This room is way too small for two people, especially when those two people were them.

"Peer pressure?" he echoes in disbelief and the corner of her mouth quirks at that. It was always amusing to push his buttons, throw him off balance, a little payback for how often he does the same to her. "As if I could ever pressure you into anything."

Beckett sifts through the office supplies, staples and paperclips, unopened packs of pencils and pens, and she could have sworn she knew where the markers were. Castle so close to her back is just… distracting her.

"Well, the pressure's definitely on now regardless," she mumbles, shoving a paper tray out of her way, stretching on her tiptoes to peer along the next shelf.

"See, that's your problem, Beckett. You need to relax, give your brain a break," Castle muses, and she insists to herself that she's imagining the building heat of his body growing closer.

"My brain wouldn't need a break if it weren't for you," she growls, dropping back down to the balls of her feet and turning to face him with a glare that has his adam's apple bobbing with a thick swallow.

He's not wrong, though. She craves a break, craves for her brain to be encompassed in a blissful blanket of nothingness, for the tension that laces through her shoulders, the pressure that pounds through her skull to be eradicated. And it's a bad idea, possibly the worst she's ever had, but standing in a room, inches away from a man who drives her absolutely crazy on a daily basis, has her wishing it wasn't.

And Castle notices.

"Beckett," he murmurs, his voice dark, rich, and she watches him reach behind him, his fingers snagging on the handle of the door, and drawing it inwards. The click of the door closing, the sound of being effectively trapped in a supply closet with him blocking her only exit, is deafening. "What else can I pressure you into?"

"Castle," she warns, standing her ground even as he takes a step closer, toe to toe with her now. His eyes are alight with challenge, that same kind of burn she's seen ignited since she joined the bet – crackling determination that matches hers, adds fuel to the fire already burning through her veins.

She's just so irritated, frustrated over this stupid case, and he's not exactly helping. But it is the first time he's felt like something more than an annoying tagalong, like something akin to a true teammate she can count on. A partner.

She doesn't want to ruin that, not when it's still so new and tentative, not when she's still recovering from the wounds he'd inflicted months ago by reopening her mother's case, but his eyes are growing darker, midnight pools that reflect the desire she feels stirring in the pit of her stomach.

"I could help you de-stress?" he suggests, his gaze flickering to her mouth, lingering.

She loses her nerve, stumbles a little as she backs into the wall of shelves. Castle doesn't follow, leaves the decision up to her, and her eyes mimic the fall of his gaze without her consent in that moment of stillness, tripping down to his mouth and caressing the seam of his lips, the smirking edge of his smile that she wants to scrape away with her teeth.

"I hate you," she mutters, and that's all the incentive Richard Castle needs to eliminate the single step of distance between them, to take her face in his hands and cradle her cheeks as his mouth descends to devour hers.

Kate moans, doesn't even try to contain it, her body arching into the broad wall of his chest without hesitation, like they've done this before, her fingers snagging in the sides of his shirt to yank him closer while Castle's tangle in her hair.

Energy explodes through her system, a white-hot sensation that's been building for months now, since she had dragged him into her interrogation room for the first time, a spark that had been smothered over the summer they spent apart, overwhelmed by the stab in her back his betrayal had left. It reignites with fierce intensity now as his hips cant into the pull of her hands, pinning hers to a shelf of pristine printer paper.

Her mouth opens on a gasp, panting for oxygen even as her head spins, tilting back against the wall to allow Castle a clear path to the column of her throat. His hands aid her in shrugging the leather jacket from her frame before they glide down her back, his palms applying glorious hints of pressure along the edges of her curved spine, and hook at her hips, encouraging the roll of her body as his thigh slides between her legs.

"Fuck, Castle," she mewls, her fingers tunneling through his hair, nails scoring his scalp when he opens his mouth at her clavicle, rakes his teeth along the sharp ridge of bone.

"Not in the supply closet," he breathes, his nose nudging her shirt out of the way, his lips trailing along the slopes of her breasts, but there's too much fabric obstructing the work of his mouth.

She wants to help, but she's useless, really, her fingers unwilling to release from the locks of his hair, the burn between her legs where the hard muscles of his thigh contract blinding her with sparks of sizzling white spots through her vision.

He's shifting, though, releasing her hips to tug her shirt up her torso, bending awkwardly to reach the taut planes of her stomach with his mouth. She momentarily loses the wonderful pressure against her core as he backs up, but she gains the hot strokes of his tongue to her abdomen, the nip of his teeth traveling up to her diaphragm, scraping over her navel and along the rungs of her ribs.

"Rick," she gasps, biting hard on her bottom lip, her cheeks flushing with embarrassment. She never uses his first name and it sounds so wrong to speak it breathlessly in a supply closet while he's got her shirt halfway off and his hands on her breasts.

His fingers frame the cups of her bra, simple black cotton with a lace trim that he brushes with his thumbs, and she's so lost in the roam of his hands, the heat of his mouth, that she almost forgets why she had been resisting him all this time in the first place.

"We don't have time for this," she chokes out, horrified at the sound of her own voice, how utterly undone he has her.

There's always been electricity between them and she had never questioned whether or not they would excel in a physical connection, but this was almost too much, becoming more than a hasty makeout session in a supply closet.

Castle growls, a noise she's never heard him make, a noise that has her hips bucking as he palms her left breast, slides his other hand beneath her bra to squeeze her flesh, tend to the straining peak of her nipple with the circle of his thumb.

"Relax. Whole point of this is for you to relax," he murmurs, traveling back up the line of her neck, suckling at the skin that throbs with the reverberations of her rioting pulse, and she tugs hard on his hair.

"Don't you dare leave a mark," she rasps, rocking forward into the cradle of his hips, feeling the straining evidence of his own reaction, a whimper caught between her teeth at the hard press of his thumb to the tip of her breast at the contact.

"So bossy," he huffs, but his lips are curled at the hinge of her jaw, and Kate turns her head, captures his bottom lip between her teeth.

She plucks the control from him with each nip of her teeth, every brush of her tongue along his, and Castle pulls her body forward, seals her flush against him and drags his hands down her bare sides to fit his palms to the curve of her ass. Her breath catches at the guide of his hands, aiding the rhythm of her hips, the grind of her lower body against his, and she's so close, so blissfully close-

"Do not answer that," Castle mumbles into her mouth, the phone she had tucked into the front pocket of her jeans vibrating relentlessly between them, just like the need inhabiting her bones, spilling through her abdomen. "Beckett, no-"

Kate closes her eyes and tries to breath, tries to tame the rapid rise and fall of her chest, and maneuvers her hand between them.

"I have to, could be about the case."

"Kate," he whines and she resists the amusement that almost breaches her arousal and claims her lips, brushes her knuckles along the seam of his slacks to shut him up before she retrieves her phone instead.

"Hey Lanie," she answers on a sigh, listening to the M.E inform her about the forensics report, how she had found something. Something that may help them solve the case and win the bet. "Yeah, okay, we'll be right there."

Beckett ends the call and pushes on Castle's chest with her hand, smirks as he shuffles backwards with a disgruntled pout, shifting uncomfortably in front of her.

"Lanie's got something," she informs him, hoping that somehow, they can just go back to normal, proceed through the rest of the day as if this had never happened.

Somehow, she doubts it could ever be that easy though, not with him.

"I heard," he mutters, reaching over her head and presenting her with the pack of markers she had been searching for. "I didn't see them until I had you pressed up against the shelves," he defends when she pins him with a glare and she huffs, plucks the markers from his grasp, starts for the door, but Castle snags her elbow.

"Castle, we have to-"

He fists one of his hands in her hair, holds her steady as he smudges a hard, unforgiving kiss to her mouth that has her body rising into him like a puppet on a string.

"We're not done with this, Beckett," he states and she arches an eyebrow before her eyes can even flutter open, intrigued by the side of this man that could hold power over her, that she finds she doesn't mind sharing the reins of control with quite so much.

"We're not?"

"No way," he huffs, releasing her to grab her jacket from the floor while she straightens her shirt, dusting it off before he hands it to her. "You're obviously still under copious amounts of stress that I can assist with. So, let's go win the bet, and then we can celebrate."

"You're rather presumptuous if you think that's how I intend to celebrate our impending victory," she muses, combing her fingers through her hair, smoothing down the locks disrupted by his fingers while he does the same.

Castle places a hand to his chest and stares back at her in feigned shock. "I never said that was the celebratory plan, but if that's what you want-"

"Shut up, Castle," she huffs, biting back a chuckle and curling her fingers around the door handle, easing the door open to check the hallway.

Still empty. They weren't gone long, a few minutes max, even though it felt like far longer. Like seven minutes in heaven, her mind supplies, and she purses her lips to repress a groan at the childish thought.

Her body still hums with a kinetic energy, an electricity that begs to surge, be released, but this case has her dignity at stake, thanks to the man peeking over her shoulder between calming breaths. They can't afford to lose and perhaps, if they win, then maybe they really can find a creative way to celebrate.

Hopefully somewhere other than a supply closet.

"On second thought," Beckett murmurs, already slipping out the door. "We'll see.