Summary: Castle and Beckett get a little too caught up while building theory together. Fluff.

A/N: This is my first fanfic ever. yeah, ever. I've read fanfiction religiously for the past four or five years, but have never really felt the urge to write until now. So I hope it's not too awful. Anyway, this story hit me like a ton of bricks while I was watching Castle and Beckett build theory a few days ago, and I had to get it out. Also, I obviously don't have a beta, so all mistakes are mine. Hope you enjoy!

Disclaimer: I don't own Castle.

"Castle, why don't we wait until we have some actual evidence before we convict," Beckett said, the words seeming overused even to her. But unfortunately, Castle never seemed to hear them.

She walked into to the empty breakroom, needing to refill her mug if she was going to stay awake any longer. It got harder and harder to stay fresh when it got this late; the busy sounds of the precinct quelled into a peaceful pur, making her ache for sleep even more.

"Come on Beckett, isn't it obvious? It has to be the husband," Castle nearly squealed as he followed her into the break room, not understanding how Beckett wasn't seeing the truth of his words.

Beckett sighed as she reached the espresso machine Castle had bought so long ago, "Just because he creeped you out a little doesn't mean he killed his wife of twelve years."

"Yes, but we can pretty much assume that she was having an affair," he said as if it were the most obvious thing about the woman. Beckett gave up on her espresso and turned around to face him. At her unsure look, Castle quickly provided proof. "The sudden weight loss, the new clothes, the dyed hair," Castle drew closer to Beckett, eager to drive his point home. "Who was she trying to impress? Not a husband of twelve years, I'm guessing."

"Okay, so the husband finds out and kills her," Beckett said, giving into the back-and-forth that was such an effortless part of their relationship.

"Exactly. The husband comes home-"

"After just finding some sort of damning evidence of his wife's infidelity-"

"And confronts her."

"She acts like she doesn't know what he's talking about, still unwilling to admit to the affair," Beckett said, uncontrollably stepping inches closer to him as they reached the climax of their theory.

"And he loses it. He pushes her against the kitchen counter in a fit of rage," he said, pushing Beckett back until her lower back gently hits the counter where her still-empty mug lay.

"Where she gets the bruises on her lower back," Beckett fired back, unfazed, as of yet, by their close proximity.

"They struggle," Castle acted out the struggle by taking Beckett's hands in his and rocking them back and forth between the two of them, as if they were pushing each other.

"She starts to break free," Beckett said as she ripped a hand free of Castle's.

"And he hurriedly reaches for a knife and stabs her," Castle finished as he shoved an imaginary knife into Beckett's side with his free hand, letting his hand linger on her waist.

Castle smiled, pleased that his theory seemed to click with Beckett, and she smiled back.

Her smile faltered, though, as she realized just how close she and Castle had become. She suddenly became acutely aware that he was simultaneously holding both her hand and her waist and had her pushed against the counter, trapping her much too close to him.

As their breath continued to mingle, Beckett felt the fog start to take over her brain. This was one of those moments. One of those moments where the attraction she tried her best to ignore forced itself up to the surface, undeniably exposing itself to both parties.

Castle closely watched Beckett's gaze, waiting for her to push him away. He knew he should back away too, but found that these opportunities were coming less often now that they were both in relationships and wanted to see where it led.

He lightly gave her side a squeeze before lifting his hand from the spot, going to brush away the mane of perfectly-straightened hair to expose more of her breathtaking face.

Beckett felt as though Castle left a trail of fire wherever he touched her, her side tingling violently. She saw his eyes darken as he brushed her hair from her face, leaving another tingling trail on her cheek as he did so.

He rarely got to see her so close, so exposed, and it thrilled him. "God, you're beautiful," he breathed.

She was used to the endless flattery he threw at her, but it was usually accompanied by an undercurrent of playfulness. Not this time. No, this actually made her cheeks redden, for she had never seen Castle so genuinely fascinated with her.

The emotions she had spent the summer trying to stamp out were now rushing to the surface. She wanted to ease the fear she saw in his eyes, the fear that she was going to push him away, slap him, and end their moment evident in his blue orbs. She was still too afraid to expose herself for him to crush her again, so she settled for letting her signal be only that she wasn't pushing him away.

That was enough for Castle. He took her hand that was still lying peacefully in his and laid it against his chest, placing both of his hands on her neck.

Her eyes flickered down to his lips, and he took that as his green light. He gently pressed his forehead against hers, letting their mouths linger centimeters apart from each other. Her eyes slid shut.

"Kate," he beckoned, breathing her name more than actually saying it. He wanted to make sure she wanted this as much as he did.

She opened her eyes and looked straight into his, wondering why their lips had not yet met. What she saw there made her knees go even weaker. He was worried. He looked intently into her eyes, trying to convey exactly what he was feeling: he was afraid of breaking them, of shattering their already fragile partnership and losing her forever. Seeing that he was just as afraid as she was, she decided to end this nonsense, to finally soothe both of their fears.

Moving for the first time, she broke their connection and pulled her forehead from his, looking more squarely into his eyes. She saw the instant look of rejection flash across his features, and made quick work of removing it. She took both of her hands and, sliding them up his chest, rested them on the side of his beautiful, distraught face. Immediately she felt the tension leave his body. His eyes fluttered closed. Repeating his gesture from earlier, she breathed his name.

"Rick."

His eyes snapped open at the sound of his rarely-used first name. They gazed deeply into each other's eyes, knowing there was no turning back; their lips finally met.

It was soft at first, with both of their lips barely parted, tentatively tasting and testing each other. After a few moments Castle pressed Beckett further into the counter as he leaned in to deepen the kiss, eliciting a moan from Beckett as she opened her mouth to his.

Their tongues met, the dam breaking. Urgency took them over. Their mouths attacked each other, needing to taste more. Their hands roved over their chests, fingers frantically searching for more contact.

He hurriedly picked her up and put her on the counter, grabbing her legs and pulling her into his body, their mouths never breaking contact. Now slightly taller than him, Beckett leaned further into their kiss, grasping the collar of his shirt in her fists. He ran his hands up her back and grasped her shoulders, pulling her ever closer to him. Instinctively, she wrapped her already parted legs around his waist, feeling him entirely against her. His arousal was now plainly obvious as she could feel it boring into her, and this seemed to fuel Beckett even more. She tightened her legs around him, her arms lacing around his neck-there really was no need for the counter now; he was holding all of her to him.

Castle pulled away from the counter, tightly holding her in his arms, took a few steps to the right, and stepped forward again to push her back into the refrigerator. He moved as close to her as he could, creating a glorious friction between their hips.

Beckett had never been more aroused, and she was only kissing the man. Her mind raced as she imagined them going further, and suddenly she needed more. She barely pushed off the refrigerator with her hips, rocking them against his, eliciting a moan from him. He roughly pushed her back against refrigerator, reaching his fingers under her blouse, ready to dispose of the vile cloth.

Suddenly, they heard someone yelling, "Beckett, Castle, you okay in there?"

Finally realizing that they were in fact in the very public break room, they broke apart quickly, Beckett finding her footing and flying back over to the espresso machine while Castle backed away to the other side of the room.

Esposito strolled in, hoping he would finally walk in on something going on between them, dispirited when he saw them on separate sides of the room. "Hey, everything okay in here? I heard sort of a banging noise."

Flustered, Beckett clamored for an answer, "Oh yeah, um, Castle...ran into the fridge."

Perking up immediately at how Beckett's breathing seemed disjointed, he took a closer look at the two adults who couldn't seem to meet his gaze. Castle was admiring the ceiling, his hair sticking up at odd angles and his shirt untucked at various places, not to mentioned the red smudges across his face. Seeing Esposito's knowing grin, Castle quickly started to rub the smudges of his face, tuck in his shirt, and pat down his hair.

Esposito turned to look at Beckett, trying to find even more evidence of the heated moment that he knew had taken place. Her back was turned to him, her hands busily making coffee, so it wasn't as easy for him to spot the tell-tale signs of a make-out session, but it definitely wasn't hard: the back of her hair was severely disheveled, as if she had been pushed up against something. Probably against the fridge, he thought.

"Oh really? Castle just ran into the fridge? That seems pretty clumsy bro," Esposito said, a smile on his face.

"I'm a pretty clumsy person," Castle provided.

"Mmhmm," Esposito hummed, unconvinced. "You sure it wasn't you that ran into the fridge, Beckett?"

She refused to turn around to face him, knowing the bright blush on her cheeks would give her away. She tried to put as much resolve into her reply as possible, saying, "I think I would know if I ran into the fridge, Esposito."

Esposito chuckled, deciding not to push anymore. Maybe if I leave they'll pick up where they left off, he thought. "If you say so," he watched as they both let out a breath. "Well, I better be heading home. Gotta get some sleep so I can get up here early tomorrow and we can catch this bastard."

Beckett turned around to face him, confident they had gotten away with it. "See you tomorrow Esposito."

"Bright and early," Castle grimaced.

"Don't stay up too late you two," Esposito quipped; he just couldn't resist. As he walked out of the break room he threw one last thought over his shoulder. "I'm thinkin' maybe the husband had something to do with it, but I'll have to wait and run down some leads tomorrow," and with that he left the precinct.

Neither of them could contain the amused grins that crossed their faces. "See," Castle said, "I told you it was the husband." He walked back over to stand in front of her but remained at a respectable distance.

"Evidence, Castle. We still need evidence."

"Yeah, but you have to admit my story sounds plausible."

"Something similar may have happened," she offered, not willing to boost his ego any more than that.

"Something similar? Pshh, I bet you he confesses to it happening just like that."

"Oh, I highly doubt that," Beckett challenged, moving closer to him.

"Oh you do? And what do you think will be so different about it?" he asked as he matched her step for step.

"Well, Rick," her voice took a sudden leap to sultry as she stepped up to whisper in his ear, "I doubt their argument ended in the same way ours did."

And before he knew it, she was gone. He watched as she sauntered out of the break room with what he assumed to be a pleased smile on her face, reminding him of the way she walked away after whispering in his ear after their first case. You have no idea, he remembered her breathing against his ear. After what just took place, he felt like he finally did have some idea. He wouldn't let her have the last word this time.

He walked into the bullpen to see Beckett filling out some paperwork. He took his usual seat beside her desk and looked at her. After a few seconds, it was clear that she was going to try her best to ignore his intense gaze. He stood and moved behind her, putting his hands on either side of her desk, almost touching her arms, and leaned down until his lips were nearly brushing against her ear. He saw her pen halt mid-word as he let his breath tickle her ear for a few seconds. "Well, Kate, I always did enjoy writing an alternate ending."

And he was gone. Kate watched as he pompously walked away, still paralyzed by his sudden movements. She smiled, taking a few moments to gather herself before attempting to write anymore. Quite the alternate ending, she thought.

A/N: Well that's it! I hope you enjoyed reading it. If you feel like it, I would really love a review. I've never gotten any before (obviously), so yours would be my first review ever. I'll stop trying to shamelessly guilt you into a review now. Have a wonderful day!