Wow, it's crazy how bad i needed that out of my system... Not sorry for what ensues ;)

Oh! And it's rated M for a reason ;) So it you don't like smut, this isn't for you...

Disclaimer: I don't own Castle. There.

Castle's gaze was resolutely fixed on the end of the corridor as he kept fidgeting in his chair, as if he couldn't find a comfortable enough position. "Well, that's unusual" his partner thought, amused, as she took in the view of Richard Castle lost in his thoughts. Except, now she stared, she saw that glint in his eyes she couldn't quite read. Something like... anger? She usually wasn't the one staring when she thought he didn't see, so, the roles were reversed. Weird. But then something seemed to click in the writer's mind as he rashly stood and stalked towards the elevator, without a look towards her. Something was definitely wrong.

He usually whined until he got her to leave with him, when it was getting late. Even if they only occasionally shared a cab, he always wanted to ride down the elevator with her, and walk her to her car, or motorcycle. But not today.

"Castle, where you going?" He stopped in his tracks and whirled around, as if she'd shaken him out of his thoughts.

"Um... I have to run an errand." He started rocking back and forth on his heels, and when she stood up, he backed away.

"Why didn't you do it right after lunch? It's only 6PM. Didn't you want to stay for the Indian order-in?" She noticed that he kept avoiding her gaze, while pressing his palm to his forehead. He thoroughly rubbed his eyes.

"I..."

"Is everything all right?" He covered his mouth with both his large hands, and sighed.

"I have to go, I'm running late." He resolutely turned around, and dashed for the elevator.

"Late for what?" She called after him, but got no answer, as the doors closed on his tall silhouette.

She was left standing alone at her desk.

"We've got him!" She jumped at the sound of Esposito's voice.

"What... What have you got?" She took a moment to register he was shoving a piece a paper in her face.

"A patrol spotted our guy in a bar, downtown."

"Okay, you guys wait for the team to drop him off, and then go interrogate him." She had a troubled look on her face, but Espo didn't comment. She started shuffling through her desk, but realized she couldn't focus on a case when all that kept coming back to her was Castle's distressed attitude.

"Umm... I have to go... take care of something. I'll be back as soon as I've checked it out. Can you... Can you keep me in the loop?"

"O...kay?" Esposito sensed something must be going on, but when Ryan collided with a really rushed Beckett, he only smirked a little, and they shared a look before watching her take the stairs exit.

She made it all the way down in barely a minute, and started scanning the crowded sidewalk for her partner's broad silhouette. She spotted him jumping into a cab. She dashed towards the traffic, but realized it wasn't him when she stuck her head inches away from the window pane, and that earned her an annoyed look from the client and an angry honk from the taxi driver, but she couldn't care less. Where had he disappeared? Castle couldn't be that far, she'd arrived on the ground floor just seconds after the elevator.

After a few moments of anger and self loathing for getting distracted by his attitude in the middle of a case; she could've texted him, goddamnit; she made her way back to the precinct. Beckett took her time walking back to homicide, because she wasn't ready to face her partners' looks, or her own rash decision of running after him. What the hell was that all about, anyway? Castle'd been behaving weird for the past days. Ever since the last weekend, actually. Something must be wrong, for him to run out in the middle of a mysterious double homicide. Involving magic tricks and unexplained events about which they debated ever since the beginning of the case.

She found a calm place where she could let herself slide against the cold stone of a corridor in the Robbery department. It was surprisingly calm, for a tuesday afternoon.

She was about to stand up and head back to her desk when she heard a deep sigh, coming from the room behind the door on the opposite wall. The men's room. Her curiosity was spiked, so she leaned to the side to get a glimpse of the inside. She nearly choked when she recognized Castle's black undershirt, his purple shirt dismissed a few feet away. So he hadn't hopped into a cab. He was hiding in the men's room of the Robbery floor. How did he get access here? Her trail of thought was interrupted when he violently shuddered. She couldn't see his face, but heard him splashing water over his face. For a moment, she wondered what she should do, before deciding she should probably go in there and get it out of him. He had looked so lost, back up there.

When she approached, she realized she had no business poking her nose in his business. She was about to back away and erase the disturbing image of a breathless Castle when he noticed her and stopped throwing water on his face, grew still and calmed his staggering breath. He gripped the edge of the sink, until his knuckles grew white.

"Kate..." She nearly didn't hear him, his voice had dropped a few octaves.

She stepped towards him, unsure of the attitude to adopt, the correct thing to say, expect when she approached, she realized how much his eyes had darkened, the black drowning the baby blue of his irises. She knew he could see on her face she had understood exactly what was happening to him. While being more than a little embarrassed and flushed, the vision of what looked like a very painfully aroused Castle turned her on. A lot. She had to admit it to herself.

After the initial shock of finding her in the doorway, that shyness written all over her face, he could only focus on her. Ever since he had written that whole smutty R-rated chapter for Nikki Heat over the weekend, never to be published, he couldn't get her out of his system. He thought by doing that it would release the tension that recently had been building up inside him. But he was wrong; it did nothing but make things worse. He couldn't do anything about it. It had grown impossible to stand by her and mentally undress her and not touch her and pretend focusing on a case he would normally be excited about, when all he could think about was her skin and her smell and her soft hands and her red, red lips and her unbelievably long legs.

She was standing there, aghast, obviously as messed up as him. He knew today would be impossible to live through ever since he'd stepped into the precinct that morning. He usually made it through the day, but this afternoon had been too much. That white blouse of hers gave nothing away, but his imagination totally made up for it, and he had to keep his attention completely away from her, fixed on the end of the corridor, or else he was scared he would do something totally inappropriate to her in a totally inappropriate place. He couldn't fight it, so he'd fled. But now she so near; too near. He felt that other kind of gravity pull him towards Beckett.

He groaned and tightened his grip on the wooden counter.

That groan and Castle's dark gaze raking over her body made her feet subconsciously bring her closer. She stared at his black eyes, his open lips, his hitched breath making his chest heaving and falling. She could imagine the hot puffs of air escaping his mouth. She licked her lips, brought her palms together and squeezed and twisted, trying not to touch him. God, she felt so aroused. He made her feel so aroused. Without her consent, her eyes raked his body in return, and she couldn't ignore the obvious bulge of his pants. Castle observed her open, red, swollen lips, and he couldn't take it anymore.

His palms directed her face closer to his, her lips to his mouth, as they locked in a rough, brutal, hot kiss. He opened his mouth against her lips, and licked them. So red. So hot. He moved to her jaw as her mouth opened and she growled when she didn't meet his lips. Her knee slid between his legs, her hands slipped in his short locks. She pulled to bring him back to her lips, and tongues met halfway, wet and slick. She was taken in a turmoil of feelings, her body claiming more and more, her lizard brain already pushing away the little rational sense she had left.

Her nails dug through his shirt while he moved to her neck, sucking, nipping, all the while his large, hot, soft palms slid under her blouse. He drew patterns on her skin, circled her waist with his large hands and started unbuttoning her blouse slowly. She moved them towards the door and managed to close it with her heel as Castle got her out of her blouse and palmed her breasts through her purple laced bra, drawing a ragged intake of air from her.

She hooked a finger in his belt and pressed him to her, and he turned her back to the wall, the cold tiles emphasizing the heat of Castle's body. She pulled his undershirt over his head, breaking their kiss, and they both regained their breaths. She grazed her nails over his skin, his eyes pressed closed. "Kate..."

"Stop. Stop talking... You talk... too much." She finished. He tried once again to call out her name, but she shut him up with a searing kiss. Lust had taken over her, and her black irises were so huge Castle could only make out a thin golden ring around her irises.

She skimmed her fingers through his hair while he softly caressed her skin as their teeth grazed each others lips, tongues fighting for control. She moved her white, glistening teeth to his jaw, his earlobe, and bit him softly. The sting of the bite and the heat of Kate's body against his brought Castle back into action. He pulled her up and back towards the wooden counter; he slid her legs behind his back bringing him closer to her, letting her feel his hard cock through his slacks by digging her heels in his butt. She reached for his belt buckle and fumbled with it until it popped open. He was so hard, it was painful. That woman was everything from the cold, determined Beckett to the softer, joyful shy Kate he rarely got to see. The lust in her eyes mixed both; she was irresistible.

He unzipped her jeans that usually hugged her ass in just the right way, but now, he wanted them off. He didn't have the patience to take them off completely so he barely pulled them enough to have the access he needed to finger her. And Oh... Oh god... She was so wet, his fingers easily slid along her clit, burying into her swollen folds. Her head bobbed back and she let a hollow breath out.

"Ooohh..."

She dug her nails in his shoulders, bringing her lips to his ear and pulling, tugging. Her hips bucked and rubbed against his crotch once he moved his long fingers against her.

She was amazed. He'd been the one barely making the day, and now he contained himself with an iron resolve that surprised her; although his boxers didn't hide his full erection.

She wiggled in his fingers, barely containing another groan, but managed to get her jeans out of the way, while he stripped his jeans and boxers.

"You are so beautiful..." She looked up to find him dazzled, but also very bothered. She grabbed his shaft and slowly stroked him while he bent down and licked her nipple, palming the other breast with one of his hand while he took her hand away from him. His head pulled back when a shiver ran through his body.

"Please... I won't be able to last long if you do this to me..."

She never expected him begging her would send intense waves of arousal to her center, and make her fight back a very animal sound.

She pulled him towards her with her heels in the cheeks of his ass once again, and he came willingly.

He started biting her neck, and sucked at it while brushing his tip against her slick, hot folds.

She gasped and bucked, again and again until he placed himself at her entrance, and locked his eyes with hers, entering her in one swift move. They both gasped, and as Kate adjusted to him, he pushed back a lock of her tumbling curls away from her face, before pulling back, nearly all the way out, and plunging his hard cock deep into her wet, tight core. His fingers played with her clit as he started to pound into her, faster and faster, passionately, as he felt himself getting close, so close... They breathed erratically, now. Her hands were everywhere. Grabbing his hair. Digging into his back. Against his tight abs. As he pulled in and out, at a faster pace, he saw she was getting close to the edge too, so he accelerated the ministrations of his hand on her clit, playing with it, all the while licking her nipples. Meanwhile, Kate bit everywhere she could. She nipped at his neck, sucking until it marked his skin. Finally, he pulled back once more and dove in her core one last time, as she muffled her scream of release. He spilled his semen in spurts, shivers shaking their bodies as they drove out their release, mouths hot, lips swollen, pupils dilated, fingers drawing soft patterns on each other's warm, sweaty skin, all there muscles finally relaxing after being tense, in control, for so long.

"Oh..."

Their muscles relaxed, and Castle sagged into her, burying his head in her chest, her head bobbing back. He stayed inside her for a while, as they slowly came down from their high, taking each other in.

"Wow..."

"Kate..."

"Shhh..."

"Kate, I lo-" She kissed him softly. Their tongues touched softly, lasy, wet. He pulled back out of her.

"We should dress." She kissed his chest before pushing him away, to grab her stuff.

"Yeah..." He was still dazed. She couldn't believe what had just happened in her workplace. They put their clothes back on, and just as Castle unlocked the door, Demming appeared in the corridor, about to push the door open. He politely saluted Castle, obviously confused, but blushed when he noticed Beckett right behind him, a dreamy grin spread on her face she tried to hide as soon as their gazes locked. She slipped past them out in the corridor, with a simple "Hi, how are you doing?".

Demming shot a dark look at Castle before he entered the men's room but the writer was too busy reliving what they'd just done while they slowly proceeded towards the stairs.

"What now?" Her eyebrows raised at his question.

"We go solve that case. We'll just see how that goes..."

Not the answer he was expecting, but he'd take it.

"Alright. After you. And rest assured, your secret is safe with me."

"It's your secret too..."

"Oh, no, I meant that you totally couldn't resist the view of me, simply dressed in my undershirt..."

"Ha! Right! You couldn't take the view of me, all week long..."

He didn't answer; mainly because they both knew it was their secret.

A companiable silence followed as they made their way back to her desk and his chair.

The End.

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