"I want it set early season 4 and Kate gets sent on an Undercover Mission, possibly to a night club or bar, where she has to get close to the perp. Maybe Castle's a bartender or bouncer and watches the whole thing. The perp ends up kissing her and fondling her and it drives him bonkers... Knowing how he feels about her and he's never even gotten to first base. It drives him so crazy that he intervenes and maybe/possibly throws himself at Kate or mauls her in front of the patrons saying he's sick & tired of waiting for her and just can't do it anymore. Of course, Kate responds to his 'caveman' act and they end up in the throes of passion. (This, of course, would be chapter 1 and chapter 2 would hopefully be a smokin hot sex scene) Gahhh!" -Purplangel

I hope I did your prompt justice. Happy Birthday!

"Can I get another for you, sir?" Castle moved his eyes away from the top shelf and cast them onto the waiting bartender.

"Two more fingers of scotch," Castle grumbled as the man poured him his next round.

It was just supposed to be a quick get-in get-out undercover mission, or at least that's what Castle thought it was supposed to be until he saw the way Beckett was dancing on their perp. He sat hunched at the bar, watching them through the reflection of the glass behind the top shelf liquors, kicking himself for not paying closer enough attention to their debrief. His chest seemed to ache every time their perp hitched his fingers under the hem of her dress, and he gripped his tumbler tighter as Beckett wiggled under his ministrations. His fury boiling with every touch from this sleazy man, Castle made himself more enraged as he reminisced on how they had gotten into this mess.

Sorenson had practically begged Beckett to assist after the last woman they had undercover had almost been beaten to death; but she had been a prostitute turned nark and , in hindsight, was not suited for proper undercover work. This guy, Lima, Sérano Lima, was trafficking coke (or was it meth?) and had setup his new base of operations in his nightclub, Suerte. They had needed someone with training to go undercover this time, and Sorenson knew the "perfect person" to assist the FBI. So, for the last four nights, Castle got to sit and watch his partner be fondled and groped by a drug kingpin, and if the Feds didn't move in soon he was going to break the guy's nose.

He wasn't even supposed to be there, that was the kicker! Sorenson had practically forbidden him from entering the bar, but when Castle had found out that there would be limited Federal guard inside the actual club he made it a point to show up as a casual patron. He kept himself far enough away that he wasn't even sure Beckett knew he was there, but he had his eyes on her almost every second she danced with the lecherous drug lord. It was gut-wrenching to see her twist and grind on another man, and it burned him the wrong way that she was allowing him to bite and touch her under the pulsing lights of the club while he had to work under the guise of a drunk to be granted one life-altering kiss. One kiss that had changed how he ached for her and now she was letting Lima bite at her ear lobe and brush his fingers along her ribs.

Castle looked down at his glass and swirled the amber liquid in a counter clock wise twist. He should just leave, she didn't need a babysitter. Beckett was a completely competent police officer who didn't need a rogue writer pretending he could defend her. He downed his drink, felt the burn of the scotch singe the whole way down, and chanced his eyes back up to the mirror for a final check before he "left it to the professionals". He roamed over the faceless crowd looking for the chestnut locks and angled jaw that made his heart sputter, but a sliver of dread pierced his gut when his initial check turned up devoid of Beckett. He wrenched himself out of his chair and turned around in time to see her being escorted rather forcefully towards the back of the club. His heart was racing and he started to breathe heavily when their eyes met and he could see the desperation in their gleam. He watched her mouth fall open with his name on her lips and confusion, anger, and hope played through the clench in her jaw and the furrow in her brow. He took a step in her direction and saw her shake her head no before being escorted into the Employees Only lounge, guarded by two men who looked like they punched down trees for a living.

Castle frantically outted the undercover Fed looming in the shadows, looking as inconspicuous as he did on a police raid with WRITER plastered across his chest. The man startled when Castle grabbed him by the shoulder and screamed into his ear.

"They took Beckett into the back! Get Sorenson in here now! She needs an assist!" The club added a backup cadence to his words that was almost poetic and his mind wandered for a second into the beauty of it before he finally caught the officer's reply.

"I can't reach him through my mike; something must be jamming our signal." Castle was furious and he grabbed the man by the tie and pulled him closer to his face.

"Get Sorenson from the back, I'm going after Beckett. Tell him that if a single hair is out of place on her beautiful head I will kick his ass." Castle threw the man away from him and watched as the Fed righted himself with a disbelieving look. Castle's nostrils flared as he turned and made his way toward the two hulking men still standing between him and his Kate.

He decided to play casual, hoping that his celebrity status could score him some behind-the-scenes action. He eyed up the two of them before making his move. The one on the left seemed like he might have opened a book once in his life and if Castle was extremely lucky he could smooth his way through those doors.

"Princesa, I've got everything you'd ever want in the back." Lima's voice was as grimy as his hands and Kate had to repress a grotesque shutter as he dug his fingers into her cradled ass. She bit her lip and tried to hide behind her hair, continuing to play the coy druggy looking for a quick lay and a fast snort. If she wanted this undercover case over and done with she'd go with him, but it bothered her that she didn't have any ties to Sorenson except for the one guy he had planted in the club. Kate was good, really good if she wasn't being modest, but even she couldn't take more than a few guys at once. Lima was scrawny and probably wouldn't put up much of a fight, but if he had more bruisers in the back next to any stashes he might have on premises she was going to need more hands than hers. It was time to play it safe, not get backed into a corner.

"I don't know, Rano," she batted her eyelashes and curled her fingers in his greasy hair, playing it up with the pet name. "I don't like to be around so many people." She let her eyes roam over his body guards and he caught her glance.

"Don't worry niña, we can ditch them at the door." He bit at her jaw and she twitched as his hand made its way under her dress. She let out a shallow giggle as Sérano grabbed her arm and motioned for his goons to follow. There was a panic that seeped into her as she was practically drug towards the back of the club. She combed her eyes over the crowd looking for Sorenson's man, but practically tripped when her eyes found the blue depths of her writer.

His eyes devoured her as Lima pulled her into the Employees Only lounge of the club, and her chest tightened as the door behind her slammed and locked. The back lounge was a stunted hallway that she found herself pressed up against, Lima's hands fondling her body. His breath was hot on her throat and she pushed him off of her as 'in character' as she could. Grabbing the lapels of his jacket, she took control of the situation and brought her lips centimeters from his own.

"Where's the powder, Rano?" Her voice came out extremely wanting, and pulled a deep chuckle from the mouth of the man in front of her.

"All you junkie whores want is the powder," she bit her lip and quelled the desire to punch the shit out of his face. "I need a little somethin' first, sweetheart." He bit after her lips as she pulled just out of his reach, tucking her chin back to avoid him. His thumb kept rubbing against the underwire of her bra and his breath smelled of cigarettes and tar. Kate leaned forward and nuzzled into his neck letting him feel like he had control over their situation.

"Please," her voice was extremely low and as begging as possible. She started to twitch her hands and bite harder into her lip, playing up her persona's addiction to the best of her ability. He pulled away and cupped her face, looking her over with his brown, cold eyes. She stared back at him, trying not to give him her interrogation stink-eye. He pulled her in for a quick kiss and turned toward one of the rooms down the hall.

"This way my, princesa de drugas, your quick fix and my earned fuck await." Kate gave a quick glance back toward the exit and had to stifle her flight urge to just run out. Sérano Lima was dangerous, and Sorenson was right when he had told her that it was only a matter of time before people started turning up dead around his operation. If she could stop him before there was a murder then all of this was worth it, but she still felt the desire to flee. Turning her back to the exit, she followed Lima into the third door on the left. It was a dark room filled with unopened crates and packing supplies. There was a set of double doors at the end that probably led to a loading bay, and that was the last thing Beckett remembered before something very hard connected with the back of her head.

"Yeah, Charlie, definitely! I'll talk to my publisher and see about putting that somewhere in the next Nikki Heat book."

Castle finished shaking hands with the bouncer and kept his thousand watt smile plastered on his face until the door shut and locked behind him. The hallway he found himself in was actually quite short and only had doors on the left side. He made his way down the hall and tried to be as nonchalant as possible. The first room was completely dark and didn't look like it had anything in it. The second door was unlocked and just had a cellar entrance in the floor along with a few pieces of office furniture. The club music was nothing more than the bass's throbbing against the linoleum tile as he made his way to the final door. Something was wrong, very very wrong, and his heart started to match the staccato rhythm of the bass as he peered into the third room.

Beckett was tied to a stool, hands behind her back; the tight rope forcing her chest forward, knees and ankles bound together while harsh shadows from few lights in the room illuminated her thin frame. Her lip was swollen and bloody, her hair in fractured disarray. A shoulder strap of her dress was torn, and her makeup was almost completely smudged off of her lips. Castle's fury reached a boiling point as Lima danced in front of her, back to the door. He was an animated talker and Castle had to commend Beckett on how she radiated strength even though she looked like she had been beaten quite profusely.

Lima walked out of Castle's view and Beckett's eyes flitted towards the door finding his through the glass. He watched her breath catch and her face slightly pale as her eyes seemed to gleam with panic. He mouthed, 'Are you okay?' and she replied with the slightest of nods. He felt the vice around his heart release as he smiled at her and she seemed to devour his presence.

"Hey, bitch, are you even fuckin' paying attention?!" Castle startled as Lima seemed to charge at Beckett, his voice cacophonous and striking. Beckett pierced him with another glare, the muscle in her jaw flexing as she ground the back of her teeth. As he stopped in front of her Lima pulled back his hand and smacked her so hard the whole stool fell over. She let out a cry that Castle could barely hear through the door, and he watched as if in slow motion as her elbow then shoulder then head connected with the cement floor.

Castle couldn't wrench that door open fast enough.

Kate rolled so that the wood of the stool was no longer grinding into her wrists and groaned as the pain started to register across her body. Her head felt like it was splitting open from the back of her skull and it was too painful to open her eyes. There was a commotion that she should probably focus on, but it hurt too much to move and paying attention meant she would have to focus and that just was not even possible at the moment. Her ears finally tuned into the fight between Castle and Sérano, but she couldn't figure out if he needed help.

Can't really help him anyway, she thought slowly as the light behind her eyelids darkened and she could feel a body close to her. She began to thrash as one of the men grabbed her, but she then felt a soothing hand at the back of her cheek and a light kiss on her forehead.

"Kate, are you okay?" He was breathing hard above her and it set her imagination ablaze with scenes of steamy sex they've never had and situations she would love to find herself in with him above her. She nodded her head, which was a mistake, and grimaced as she replied.

"Yes, it's just—it's too bright for me to open my eyes."

She could feel him lean forward and she held her breath as he placed a cooling kiss over both eyelids. Kate let out a stuttered breath against his skin and she felt him smooth down her hair and tuck it behind her ear.

"Castle," she whispered, feeling his forehead meet hers. "Can you untie me now?" He tumbled over a profuse amount of apologies as he fumbled with the ties at her ankles first. There was a small trill in her chest as he moved his hands up her legs to the second set of ties and she smiled as he righted her dress for her as he twisted her to work on the ties at her wrists. His fingers lingered at her wrist and she curled her hand down to twine his fingers with hers.

"Do you want to sit up?" he asked tentatively. She grumbled an answer and he chuckled. "Fine, fine, you don't have to move." She had just let out a small chuckle when the double doors at the end of the room burst open. Kate flinched from the noise and grabbed her head as orders were barked from Sorenson as him and his men fanned the room. Sérano Lima was instantly cuffed and escorted out of the room, still quite unconscious, and Sorenson quickly trudged up to Kate and knelt beside her.

"Katie! Oh, God, Katie are you alright?" Soreson had pulled her from the floor in a sitting position and Kate let out a small groan at the jerky movement. Castle reacted and punched Sorenson so hard that he fell back on his ass, dumbfounded. Castle cradled Kate to himself as she moaned and cringed into his chest. She shielded her eyes into his shirt and tried not to pass out at the new angle she found herself in.

"What the hell, Castle?" Sorenson growled as he picked himself up and dusted off his pants. Castle gently lifted himself with Kate in his arms and squeezed her to his chest. His presence was all encompassing and she found herself wanting to kiss the skin beneath his strapping button-up.

"I told that Fed I sent out to you that I'd kick your ass if she was hurt." Kate could feel his words rumble in his chest and placed her hand on his shirt with a small squeeze.

"Castle, can you take me home?" She opened her eyes just enough to see the anger in his face be replaced by concern at her timid request. She moved her hand up to cradle his face and she felt a quick kiss press into her palm.

"Yeah, let me get you home, Kate."

"I'm fine, Castle."

"You might have a concussion, Kate, at least let me call Lanie."

"No, I don't have a concussion, Castle, stop worrying. Just, help me get into bed."

Castle let a smile play on his lips at the insinuation and helped her walk to her room. She was steady on her feet and completely conscious the entire way home so he wasn't worried. Kate just seemed battered and bruised which caused him to just want to be around her. He needed to protect her, and he'd stay as close to her as he could for as long as she would let him. But for now, he just stood awkwardly in her room trying not to seem too out of place.

"I'm going to take a quick shower, Castle, just don't touch anything." He had almost jumped when she spoke and she let out a chuckle as she looked back over her shoulder before closing the bathroom door. He felt that clenching feeling in his gut as soon as she was out of sight and he growled at his over-obsession. He ran his hands over his face trying to rub the feeling away, but all he was left with were the images in his head of her grinding on their suspect and the conflicting feeling of her letting him kiss her eyelids. He wanted to kiss her again and hold her; there was a primal urge inside him to curl himself around her and keep her safe. It was a ludicrous idea when his twenty-first century non-sexist mind caught up to his caveman fantasty. She didn't need anyone to protect her, least of all a writer pretending to be a cop who owned a life sized Boba Fett that he kept in his bathroom.

He heard the shower shut off and had a slight moment of panic. He wanted her, his blood had been boiling for hours and he was extremely conflicted with wanting to pin her beneath him in a fit of carnal lust and wanting to bundle her up and put her to bed. His mind stopped when she walked out of the bathroom, silk robe clinging to her slightly damp body and her hair swept up in a pinned braid. His eyes watched her as she flitted around the room grabbing clothes until she stopped and turned towards him.

"Sorry, I should have –" she stuttered over her sentence and he noted a deep blush that great across her cheeks and burned down her throat. She wet her lips and he watched her eyes flit to his. He took a few steps toward her and her hands clenched around the pajama pants and top that she had in her hands.

"I watched you dance tonight." Her face burned a darker pink and her nostrils flared at his admission. "I didn't like it." He was closer to her now, fiddling with one of the drawstrings on the pajama bottoms that she clung to.

"You don't like how I dance?" Her question was ragged and she had a fake air of annoyance that he easily picked up on. Her eyes were trained on him as he moved his hand up her arm, letting only his fingertips touch the silk fabric of her robe. Only after watching her forearm erupt in goose bumps did he reply.

"I loved how you danced." He caught her gulp on the 'l' word as he continued. "I just didn't like how he touched you." His fingers had stopped at her clavicle and he took note that she was holding her breath. He knew he was crossing the line that they had danced around for years and he really hoped she was as ready as him to take the next step.

She leaned forward and he could feel her breath at his chin. "How did he touch me?" He gulped as she looked up at him from under her lashes. Her eyes were dilated, dark and murky with longing and accented with specs of warm gold. Easing his arms around her body he lowered his hands to cup her ass, gently squeezing as he pulled her flush to his chest. She let out a hard sigh as he rocked her body against his; fingers still griping her flesh and slowly bunching up the back of her robe.

"His lips were on you." It was just a statement but he could feel her body grow warmer and in turn he felt himself grow harder. Rocking himself against her he finally worked his hands under her robe. Her skin was blazing, and she let out a sigh as his open palm kneaded the flesh at her hip. Castle dipped his head forward and hovered his lips just above hers. Kate's arms had found their way around his neck and he could feel her fingers pushing into the back of his skull, urging him to budge the rest of the way.

Castle moved his nose slowly against hers, muttering. "You smell like him." He watched her eyes slightly bulge at his observation. Her mouth opened in what might be a protest, but shifted to a moan as he moved his hand from her hip to the base of her ribs. As her eyes slid closed he made his move and caught her lips in an aggressive kiss. He squeezed her body, arms completely wrapped up in her skin. Her lips tasted like honey and he didn't realize it could get any better until she moaned and he felt her tongue begging for entrance. In that instant he realized what addiction was and he knew he would never be able to quench his thirst for her.

She pulled away and caught her breath, cradling his face between her palms, clothes forgotten on the floor, as she panted. "You should do something about that." Her voice was breathless and he felt a rumble in his chest as he attacked her mouth again. She had given him permission to proceed, and that's all he needed.

"Aaaah, oh God," She was biting into his shoulder as he took her against her bedroom wall. He had been nothing but harried grunts and groans ever since he had ripped her robe away and thrust her against the wall, fingers already knuckle deep into her sex. He twisted and moved his wrist, twirling his fingers against her inner walls making her squirm against his hand, all the while busying his mouth with the side of her neck. She clawed at his back, letting her fingers get caught in the fabric of his shirt so she had something to pull on, as he thrust a third finger inside of her making her scream. Her toes curled and she arched against the wall, his name vibrating in her throat as she came around his wonderful, blessed digits.

"I can't stand that he was touching you." She opened her eyes to an ocean of blue and was swept away by their rising tide of need and love. She wanted to apologize to him, to admit to him that when Lima was groping her she was fantasizing that it was his hands teasing her. Kate pushed up into his lips trying to comfort him with her body, to prove to him that she wanted this too.

He responded with a flick of his tongue against her lips before delving into the depths of her mouth, seeking her warmth. She felt his fingers slip from her sex, a small moan of loss left her throat at their absence, as he picked her up and walked with her to her bed. He was cradling the back of her head, ever wary of her recent injury, and she wrapped her legs around his hips in hopes of gaining some friction.

"You have too much of your clothing on, Mr. Castle."

He groaned into her mouth as she purred out his name and he broke apart only to grind himself against her as he toss his shirt near the corner of the room. His jeans caused a sweet friction against her center, but she was more than happy to see them join his shirt on the floor.

"Better, Ms. Beckett?"

Her body ached with need and she pulled him back to meet her lips. "So much better," she whispered before sliding forward and nibbling his ear. He growled and attacked the pulse point at her neck, his tongue working down to her clavicle as his hands fondled her breasts making her gasp at his ministrations. His hands mapped her body, worked her flesh until she felt boneless; his tongue dipping into her belly button and his lips whispering against her skin. He caused sounds that she had never heard from herself to bloom from her throat and in a moment of pure bliss she likened herself to an instrument finally being played by a master.

Kate finally felt him at her entrance, the head of his penis teasing her with its presence. She lifted her hips and felt the pressure at her core as his tip pressed into her. Her eyes had rolled back into her head as he pushed himself fully into her wet heat, his thumb circling her clit.

"He will never-" Rick grunted, "ever, touch you again." He punctuated his words with thrusts into her body and she dug her nails into his back as he continued to rock into her. Kate's body was glistening with a light sheen of sweat, and as he picked up speed, one of her arms slipped from his back which caused her to cling to his bicep to anchor herself closer to his body. He moved his arm to brace himself on his elbow while his hand moved to again cradled her head. She felt completely enveloped by his skin as he brought their foreheads together and kept his eyes trained on hers. A heated bubbling begin to churn in her belly and as she ascended into her climax. As she reached her peak, Kate ground her lips and her hips into Castle and was rewarded with his sweet release in time with her own. She let out a keening mewl around his lips as he slowed his thrusts to match the slowing cadence of their heartbeats.

"Rick I-" he silenced her with his incessant lips, biting into her soft flesh before pushing his tongue in to dance with hers. She let him have his moment of control as he pulled out of her and she instantly felt his absence. She sighed as they turned together on their sides, lips still playing against each other. He pulled back and kissed across her cheek, up the side of her face and into her hair. She let out a faint giggle and Castle rubbed his nose into her chestnut locks, still damp from her shower. They finally parted, eyes full of mirth as she snuggled into his side and he cocooned his arm around her shoulder.

"Rick," she tried again, hearing him hum out a response that he was indeed awake and listening. "Thank you, for helping me get home today, and taking care of me."

She could practically see his cocky smile as he replied. "You know, Beckett, you could just thank me for the sex. I have been told I'm quite good, it wouldn't be new news." She let out a snort of laughter as she buried her face into his chest.

"I don't think I should inflate your ego anymore than you just did," she teased as she traced her finger against his chest.

"I'll take that statement as thank you, then."

"You would!"

"Or I could just take your screams of my name as I made you come with my fingers as proof enough." His voice had dropped again and she could feel her face burn as she vividly recalled the action. He let out a light chuckle and plopped his head back into his pillow. Kate sat up and quickly threw her leg across his hips to straddle him. His eyes widened at the action as her naked body leaned forward and she peppered kisses down his sternum. She let a salacious smile pull at her lips as she ground her hips into his pelvis.

"Or I can prove it."

"Oh, Beckett, definitely prove it."

HAPPY BIRTHDAY , SUZ! I hope it's everything you wanted and more! Love you so much!