A/N: This is a fill for a prompt someone sent me on tumblr. "What happened while Castle and Beckett were locked in the trunk during Pandora." Takes place right after Gage locks them in the trunk. It's rated M for a reason folks, so if it's not your thing, turn back now. All mistakes are my own. Enjoy! :)

Disclaimer: I do not own Castle or anything associated with the show, but the inspiration it gives me is spectacular.

Desperation

It's dark. In fact, it's so dark that if Castle couldn't hear Beckett's soft breathing beside him he'd be worried that he was all alone. They're locked in the trunk of a 1967 Pontiac GTO and as roomy as it looked on the outside, it's not the best place to be locked in with another person. It's been a while since Gage forced them in and shut the lid, long enough to know that he's long gone and they're all alone.

Kate's been jealous ever since she learned that Sofia Turner was another muse for one of Castle's characters. She's tried not to let on that it bothers her, but it's getting harder to do. She likes to act like being his muse is no big deal, but truthfully it's grown on her. She doesn't want to share him. She doesn't want him to be fascinated with anyone else. She saw the way Castle and Sofia looked at each other. He's not hers, but she doesn't want anyone else to have him.

The longer she lays there the more she thinks about it. She's not sure what's going to happen next or how long they're going to be stuck before someone finds them. Castle's been unusually quiet and she's about to ask if he's alright when he decides to voice what he's been thinking out loud.

"You know, I was just thinking about what Clara Strike would be right now if I'd continued following Sofia around."

She rolls her eyes, thankful for the darkness of the trunk. "Really? We're locked in a trunk and that's what you're thinking about?"

Kate feels him shift beside her and she has to suppress a gasp when his leg comes to rest in between hers.

"Why Detective Beckett, do I detect a hint of jealousy?"

It might be the dark, tight space they're in or the way his leg is pressing against her, close to where she really wants him. Or it could be that they don't know what's going to happen next that makes her lose all sense of self control.

"I don't want you to think about her, Castle." She turns her face so that her words come out in hot breaths against his neck. She smirks when she hears him swallow and she wishes that she could see his face.

"And why's that" he says, shifting his leg a little higher between hers.

She doesn't hide her gasp this time as she brings her hand to his chest, gathering his shirt and pulling him closer to her. "Because, she isn't me." She hears his soft growl seconds before she presses her lips against his.

Castle seems startled at first, but it only takes seconds before he's responding to her and pulling her deeper into the kiss. She rolls her body slightly until his leg is pressed right where she wants it and this time he growls into her mouth.

He pulls back until their lips separate, their breaths still mingling together. "She could never be you, Kate. You're so much more."

She doesn't need his words right now; she just needs him pressed up against her showing her how much she means to him. She presses her lips against his again as she rocks against his leg, letting her whimper flood into his mouth. His tongue slides into her mouth, exploring and driving her mad with need.

His hand finds purchase on her hip as she rocks against his leg and he lets his fingers slip under the top hem of her pants. She gasps, pulling away from his lips when his cool fingers brush over her skin.

"Tell me what you want, Kate." His voice is husky as he whispers his words and she shivers when his breath caresses her face. She reaches down and flicks open the button on her pants then drags the zipper down. It's too tight of a space to do much more, but this will do for now. His hand is still resting on her hip and she reaches for it, dragging it around to the front of her pants.

He lets his fingers dip under the edge of her panties and she shivers with anticipation, but he doesn't go any further. "Please, Castle, touch me please."

His lips find hers again as he slips his hand further into her panties. He groans when he finds her wet and ready for him as he drags one finger down through her folds and back up to her clit. Her hips buck into his hand seeking more pressure and he obliges. He presses his thumb to her clit working it in small, tight circles until he finds an amount of pressure that makes her moan.

Letting two of his fingers dip back down into her wetness, he coats them with it before pushing them inside her. She's tight around his fingers and he stills inside of her to let her adjust while he keeps rubbing her clit. He stops his assault on her lips to kiss down her neck, trying to reach as much of her body as he can.

He starts pumping his fingers in and out when she rolls her hips, setting up the best rhythm that he can in the tight space of the trunk. She alternates between whimpering and moaning as he works her towards climax and before she can stop herself the words are spilling out.

"Did you touch her like this?"

He slows down for a beat before speeding right back up and she wishes she could see his face right now. She's not sure where the question even came from.

"Not like this. Never like this, Kate." He curls his fingers inside her and she cries out as he hits that perfect spot inside her.

She wants to ask him what he means by that, but his fingers are doing sinful things to her and it's just too good.

"Yes, right there, please don't stop." She's lost her ability to ask him anything else, can only beg him to continue what he's doing. She never wants him to stop making her feel the way she does right now.

He rubs her clit faster as he continues working his fingers inside her and she tightens around him, crying out as she comes. He keeps his thumb pressed to her clit, prolonging her pleasure as she comes down from her high. He waits until her walls stop clenching around his fingers before he slowly pulls them from her body and lifts them to his mouth. He groans when he tastes her, silently wishing they weren't in such a tight space even more now.

He licks his fingers clean and then leans in to kiss her again, letting her taste herself on his tongue as he worships her mouth. He keeps up his ministrations for several minutes until the need for air becomes too much, the stuffiness of the trunk starting to take its toll.

They're quiet for a few minutes, each catching their breath and contemplating what just happened between them. They haven't talked about anything and what just happened could potentially make or break them.

"Kate, I know this isn't the best time to have a serious conversation, but I need to know what you're thinking, please."

She's about to answer him when there's a rustling sound from outside and the trunk pops open. She groans when she sees their previous escort standing there holding the black bags that covered their faces the first time.

As they start to climb out of the trunk she leans over and whispers in Castle's ear. "I can't wait to get this day over with and go finish what we started. My place after work, bring food and an overnight bag, you're going to be exhausted by the time we're finished."

If she's going to make promises like that, talking can wait.