AN - AU early season three. Written for Castle fanfic Monday. Part one of two.

"Espo! Psst!"

Esposito startles and slams his elbow into the drink machine, slopping Mountain Dew all over his sleeve. Dammit. He really shouldn't have gotten out of bed this morning.

"What?" he snaps at Ryan, who's peering around the break room door like he's trying to be all covert and shit.

Ryan shoots a nervous look at the bullpen before holding up his phone. "Beckett says we have to come get her." His lips twitch. "Like, right now."

"Why? Where is she?" Espo shakes his dripping sleeve and looks around for a napkin or a paper towel or anything absorbent. There's nothing, because he works with a bunch of inconsiderate slobs who don't know how to find the supply closet.

"Uhhhh…" Ryan makes some sort of strangled cat noise while his face spasms again. "I don't know where she is exactly. I mean, sort of, but not precisely."

"That makes no sense." Esposito frowns. "And what's wrong with your face?"

Ryan snorts into his hand. He's laughing, that's what's wrong with his face.

"Bro, I don't have time for this bullshit," Esposito sighs. "I'm exhausted. We've been up since the ass-crack of dawn."

Some inconsiderate vic got himself murdered in the actual fucking sewer, so he and the team spent sunrise up to their ankles in filth and rats. Except for Castle. He managed to remain on the clean, rat-free street by arriving late with a coffee in each hand.

"Sorry!" Castle had shouted down the manhole. "I would come down, but my hands are full!" He'd held up the coffees, his face all whadda ya gonna do.

And Beckett didn't even call him out on that shit. She claimed it was because one of the coffees was hers. "I like my coffee without sewage," she'd shrugged, but Espo had caught the look on her face when she'd first seen Castle, and it made him want to gag almost as much as the garbage stench.

It's not that he doesn't want Beckett and Castle to finally admit their very fucking obvious feelings and get together, it's just that he wishes they would get a move on so they can all stop pretending. And maybe so he and Ryan can mock them a little. Mocking Castle would definitely improve his day.

"Okay, okay," Ryan says now. He turns and smiles all crazy at Karpowski, who's eyeing them suspiciously from her desk. "Keep your voice down. You know that sketchy escort service over on 17th and McMillan?"

"The one near our crime scene?"

"Yeah. Beckett's trapped inside."

"What? That makes even less sense." Espo rubs his throbbing temple. None of the leads have panned out on their case, his head hurts, he's starving, and now this. "How did she get trapped in an escort agency?"

Ryan chokes back another laugh. "One guess."

"Castle? What the fuck is he doing at an escort agency? He's supposed to be getting our lunch!" Seriously, this is not cool. The four of them are supposed to be a team, regardless of whatever weird ass unspoken thing is going on between Castle and Beckett. Teammates don't leave teammates without lunch.

"I don't know. Beckett called for the closest squad car, but she wants us to try and get there first. She doesn't want the… um" Ryan swallows more laughter. "...details of the situation to get out."

"Details? What are the details?"

"Awesome." Ryan dissolves into completely unprofessional giggles. "The details are awesome." He grabs his jacket from his desk. "Let's go. We just have to watch out for the armed hooker."

Espo sighs as he follows Ryan to the elevators. Armed hookers and Castle? He definitely should have stayed in bed this morning.

"If you don't stop laughing I'm putting the gag back on." She's going to kill Castle. "This is not funny."

"I'm sorry. I'm laughing because I'm nervous." Castle takes a deep breath, but it doesn't seem to help. "It's not every day I'm locked naked in a cage with you. It's nervous laughter."

Kate shoves her phone down her shirt into her bra, hiding it in case the crazy women who locked them up comes back before Ryan and Esposito can get here. "You're not nervous, you're enjoying this. And oh my god, no one is naked."

He's not. Their captors left him his underwear, and that means he's not naked. Her breath is coming short because they're hostages, not because Castle's bare arm dangling from the cuff is doing amazing things to his bicep.

"I mean I'm nearly naked," Castle clarifies from his seat on the floor. "You're not naked at all. Unfortunately."

"Seriously?" Kate ignores the stupid surge of heat along her skin and forces herself to make eye contact. Angry eye contact. "You're going to make jokes? You feel like that's your best course of action right now?"

"Sorry! Sorry, I told you, I'm nervous. I'm inappropriate when I'm nervous."

"Only when you're nervous?"

That's it. Just act normal.

"I said I was sorry! I'll stop talking." He pretends to zip his lips with his uncuffed hand. "That way I won't be inappropriate."

"All of this is inappropriate, Castle!" Kate bursts out, unable to stop herself. "We're locked in a room in a brothel, and you're handcuffed to a cage in your underwear! I don't even understand how this happened! Why do you even know about this place?"

He gestures with his free hand all casual, like they're discussing a case at the precinct. Like he's clothed. The movement makes his shoulder muscle flex, not that she notices.

"Years ago I talked to some girls here. For research, Beckett," Castle rushes to clarify at her raised eyebrows. "Derek Storm interviews that call girl witness in Storm Rising."

His face falls at her blank look. "I thought you'd read all my books?"

Kate cannot believe the touch of hurt in his voice. "I'm sorry if I can't recall every call girl Derek Storm interacted with in all twelve books. Now that I think about it, it was something of a theme with him. I wonder why?"

"Why are you getting so bent out of shape about this? I solved our case! We know who the killer is."

"Why am I - ?" She can actually feel the blood rushing to her head. "Oh, I don't know Castle, maybe it's because you were supposed to be getting lunch, but instead you are at an escort service, handcuffed to a cage in your underwear, and now we're both being held hostage by multiple murderous prostitutes?"

Castle sighs, like she's being so unreasonable. "You're making it sound weird! I told you. After I left the precinct I couldn't stop thinking about that symbol the vic had drawn on his arm. All of sudden I realized it's the Chinese symbol for pleasure -"

Kate snorts. "You 'all of a sudden realized'? Because you know so many Chinese symbols off the top of your head?"

"What?" Castle sounds put out. "I might, you don't know."

Kate rolls her eyes so hard it hurts her head.

"Fine," he huffs. "I remembered the symbol from their business cards. It wasn't far, I thought I could just stop in, ask a few questions. That woman brought me back here to wait, said they were going to get the manager."

"Stop. She brought you in here to wait - a windowless room with a cage - and you didn't find that suspicious? It didn't occur to you that you should leave?"

"No, it did!" Castle sounds way too indignant for a half-naked man handcuffed to a cage. "That's when I tried to call you, but then that red-headed woman came back with reinforcements. They took my phone and my clothes and handcuffed me." He shakes his cuffs against the bars for emphasis.

Kate takes a deep breath and forces herself to at least pretend to be calm. "Okay, so they detain you because you know they're guilty, and they're trying to buy time. I understand handcuffing you, but why did they take your clothes?"

"They think I'm handsome? Sorry! Sorry," he says immediately off her furious look. "Who knows? Maybe they're panicking. They don't seem like they have a solid plan."

He leans forward, his hair falling over his forehead, his stomach muscles bunching up, and her traitorous heart kicks up a notch. "You know, Beckett, the real question is - and not that I'm not glad to see you - but what are you doing here? How did you know where I was?"

Kate licks her dry lips. "The prostitute called me and told me to pick you up. She said your appointment was over, but they couldn't get you to leave."

"That is not what happened. Now you're just being mean."

Kate narrows her eyes. Not mean enough. "The prostitute called me with your phone. She said she'd found you unconscious in the street. Gave me this address."

It'd taken her ten minutes to get here. Ten minutes of sick fear and adrenaline, her only thought to get to Castle. Kate had been so focused on him that she'd apparently lost her mind and forgone basic police procedure. She'd walked right into this room and their trap, the door locking behind her just as she realized it was a set-up. The first clue being - obviously- naked Castle.

Kate chews her lip, grateful to have something to think about besides Castle's state of undress. "Why did they call me? Now they have to deal with both of us."

"That's my fault." Castle frowns, all serious, and Kate refuses to notice how that somehow makes him look hotter. "I told them I was your consultant at the 12th. I maaaaay have given them your card."

"You carry around my cards? Oh my god, give them to me."

"I'd love to, Beckett, but they're in my pants. Which I don't have." He stretches out his legs along the floor, just in case she hadn't noticed his firm, bare thighs.

"I can see that!" Kate snaps out loud. Oh boy. Deep breaths. "You're sure they didn't say why they wanted your clothes?"

"Yes! There was less explaining and more gun waving and yelling. I didn't ask."

"Well then why…why did they make you put on those underwear?" Kate waves her hand in the general direction of his crotch and is careful not to look directly at him. The underwear in question are a pair of slinky black silk boxers that are on the small side and…very clingy.

"What do you mean?" Castle says, nonplussed. "These are my underwear."

"Those are your underwear?" Of course they are. "Why do you have porn star underwear?" Of course he has porn star underwear.

"These are not porn star underwear, Beckett. Porn stars don't wear underwear. Duh."

Kate takes yet another deep breath and tries to count to ten. She only makes it to four and a half.

"Okay. We'll talk about your underwear later." What is she saying? "Or, you know, never. Now explain to me why you didn't leave when you were told to wait in a room with a cage."

"I don't know! I guess I thought it was a themed waiting room or something. You know, give prospective clients an idea what the place offers? I didn't realize I was walking into a sex dungeon."

Kate glances at the cage, noting that it isn't bolted to the floor or ceiling. "This isn't a real dungeon. It's just pretend." She still can't look at him.

Castle leans back against the bars like he's in bed and no, no, don't think about Castle naked in bed. "Isn't that the point?" he asks. "The pretending? I thought all places like this had dungeons."

Kate cannot, cannot discuss this with him while he's all …she just can't. "God, Castle, I don't know, maybe this is just a particularly well rounded house of prostitution. I don't frequent places like this. Unlike some people, obviously."

Kate knows that isn't true, but she's mad at him, her stomach twisted into knots of remembered panic and something else that she won't really let herself think about.

"I've explained that I know about this place because of research, and what do you mean you don't know?" Castle's staring at her like she's just told him the truth about Santa. "I thought you had a vast and detailed knowledge of all things sexually unusual?"

Kate actually feels herself flush. Damn him. Damn him and his stupid tiny black silk boxers and surprisingly well developed chest, and the fact that he's cool as a cucumber while she's completely flustered.

And it's not like…it's just a surprise, okay? Two years and constant innuendo, but Castle's never been undressed. Even when she'd stayed with him at his loft last year he wasn't half-naked. And yes, she's being ridiculous. It's just that she's never seen him without a shirt before and it's …it's unnerving, is all.

Why isn't Castle freaking out? If he were freaking out, she would have to compensate by not freaking out, and concentrating completely on getting them out, instead of accidentally fixating on Castle's naked chest. But she's fine. Fine.

She has to be fine, because this is serious. The madam of a house of prostitution has seriously locked them in what Kate suspects is the storage room, and okay, when she articulates it to herself like that it just sounds dumb, and please, please let Ryan and Esposito get here before the squad car, and will Castle think it's weird if she drapes her jacket over his chest?

"Shh!" Castle says suddenly, even though she isn't talking. "What's that?"

Kate turns at the sound of a ruckus outside the door. "It's probably the guys - "

The door bursts open. The tall redheaded woman from earlier rushes into the room, followed by two more women, one in a tailored pantsuit, the other in fishnets and a bustier.

"There's a 'three hookers walk into a bar' joke in here somewhere," Castle says from behind her.

"Shut up," the redhead snaps, her voice shrill. "The police just pulled up, you're out of time."

"We're out of time?" Castle says incredulously, as Kate instinctively reaches for the gun that isn't there. "I think you're confused."

"I said shut up," the woman screeches. She pulls something from behind her back and everything goes into slow motion. Kate tries to step in front of Castle but instead collides with him as he tries to step in front of her. She falls to the ground, Castle still dangling from the cuff, his naked limbs all around her.

"Get up!" The woman is screaming now, clearly losing it, as she points a … camera. She's pointing a camera at them.

Kate gets to her feet, Castle clambering up beside her, his free hand wrapped around her wrist.

"Now," the woman says, gesturing to Kate. "Give me your clothes."

Many, many thanks to Kate Christie and Alex (caffinate-me) for the beta-ing and the the cheerleading.:)

Part two will be up in a few days. Thanks for reading!