The Best P.I. in N.Y.C.

A/N: This takes place during 7x12. We're gonna pretend that Sofia Del Cordova does not come in and interrupt them. :P (Slightly mature rated). Enjoy!

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"So, did you figure out where the white limo took Ana?" Kate asked, and Castle frowned, looking down at his laptop monitor.

"I can't even figure out whose limo it was. The taxi and limo commission has thousands of limos registered, but they're not broken down by color so I'm working on plan B."

"Okay, well … ready to get out of here?" Kate smiled flirtatiously. "Call it a night?"

They both stood, and Castle replied, "Oh. What's your rush, doll? Why don't you stick around awhile, give those stems of yours a rest?"

Kate, who seemed to follow Castle's train of thought, followed him to the windowsill where he was preparing their drinks. "Could I? I'm all alone and this is my first time in the big, scary city."

Castle loved when she played this game with him. She wasn't one to shy away or roll her eyes, but rather take on the role he was offering her and go with the flow. It brought excitement to their relationship, this flirtation, and he loved her all the more for her willingness to participate in his favorite theater.

"Spare me the tall tale, precious. A dame like you? You've got an angle." He poured her a glass of scotch, which she readily accepted with an amused grin on her face.

"You're pretty quick for a gumshoe."

"Come on. Spill the story. Time is money and I've got none of either."

"All right, I'll give it to you straight. I'm just a girl looking for a private dick," Kate murmured, and before Castle knew what was happening, her palm was cupping him through his pants.

He jumped, making Kate giggle. "Whoa!" He took her glass and set it on the windowsill, blood pumping harder than it was only moments ago, making him a little dizzy. "Then your search is over, sweetheart."

Kate laughed as Castle wrapped his arms around her and spun her around, his mouth frantically seeking hers. He pushed her back against the window as she slid his jacket off his shoulders.

"This here … this is the double? Got it." He felt clumsy as he tried to open the buttons on her shirt. The flimsy little things were not easy to handle, but eventually they popped free and he was able to work his way down the front to the next one.

"There you go," Kate sighed against his shoulder, using her own fingers to deftly remove the buttons from his shirt. She got there faster, and soon it was lying in a heap at his feet on top of his jacket.

He dipped his head again, kissing her neck as she ran her fingers up and down his bare back. Her touch, like cold lightning, sparked prickling, electric shivers to zing up his spine. It never got old, this anticipation; the way she always kept him guessing. He never knew where she was going to go next, as Kate Beckett rarely stuck to any kind of routine.

"Castle," she sighed against his neck, and it was enough to make him want to rip her shirt clean off her body. When she made those sounds… god, they were like gasoline in his veins, igniting his fire to burn even hotter, even brighter. The beginning of a moment like this between them - in public and hurried, but not cutting corners - made him feel like he was flooring the Ferrari down a deserted rural road; fast and exciting and a little dangerous… fun.

He started to tug impatiently at the hem when one of the buttons wouldn't budge, but her hands stopped him. "I got it babe." She guided his hands down to her pants, which were much easier to manage, and she worked on the buttons of her shirt herself. He was grateful she'd given him another, just as important (if not more so) task. It was humiliating not being able to strip one's wife properly, in any situation, but especially not when they felt this heightened sense of urgency.

(He could see in the heaving of her chest that she felt it too. This need rushing in like a flash flood, threatening to drown them. It only heightened his sense of urgency.)

Soon her shirt and jacket were lying on top of his, and she was able to shimmy out of her pants before Castle placed his hands on the backs of her thighs and lifted her up, setting her carefully on the short bookcase. It felt sturdy enough under her slender weight.

He couldn't even think. Her hands were in his hair, scratching down his biceps. Her scent was everywhere, and her warm, soft skin was just screaming to be touched. He didn't even know where to start. (It was always like this with Beckett, Castle realized. Everything about her was all-encompassing, overwhelming. He'd had her a thousand times and it was still not enough for him. Every time felt brand new somehow. She was magic like that, he supposed.)

And then her fingers were at his stomach, coming between their bodies as she tried to unbutton his pants. But he kept pressing against her, wanting not even an inch of space between them.

"Castle," she reprimanded softly, even as he tugged her hair back the way she liked. He licked the pulse point on her throat and he could feel her shiver. "Please," she urged, and her fingers gripped harder.

It took a considerable amount of effort, but he tilted his hips back far enough to give her space, all while kissing his way down her throat to the top of her lacy periwinkle bra. He could see in the dim light of the office that his lips were giving her goosebumps.

Kate's breathing was ragged; he could feel it as his hands gripped her on either side of her waist. He dug his nails in slightly, then ran his teeth against her collarbone. "Take them off, Beckett," he murmured into her skin. He could feel her fingers shaking, but eventually the trousers slid down his thighs.

He didn't even bother kicking them off. He just pulled down his boxers until they were bunched around him like ruffles on a wedding dress and set his eyes on his prize. She bit her lower lip in anticipation, cheeks flushed pink, waiting for him.

Castle hooked a finger into Kate's underwear, sliding inside her with ease. She gasped and groaned, and he decided by the feel of things, neither of them wanted to wait much longer.

But that didn't mean he couldn't make her beg for it.

"What do you want, doll?" he said, taking her chin in one hand and sliding in a second finger with the other.

Her eyelids fluttered closed. "I –"

He pushed in again, slowly, deeply, and curled his fingers just so.

"Oh, Castle…"

"That's Mr. Castle, to you, Miss."

Kate reached up and tugged Castle's neck down to kiss her. He let go of her chin so he could shove his hand through her silky hair.

Then she pulled away, and whispered against his cheek, "You know what I'm lookin' for." Her hand slid between them, her long, delicate fingers gripping him hard enough to make him draw in a breath.

"You got it, sweetheart." Castle removed his hand from her tousled hair and pulled her hips to the edge. He slipped his fingers out from inside her, tucked the thin fabric to the side, and swiftly buried himself in one ungentlemanly thrust.

Kate cried out, wrapping both arms around his neck. Her body was already twitching, anticipating what was to come. "Rick…" she sighed, and bit hard onto his shoulder.

It was fast and it was clunky, causing several bookcase ornaments to fall from their post and clatter to the floor. But they didn't care. It was reckless and wondrous and new, and the thrill made everything feel heightened, their senses sharper. And then it was over just as quickly as it had begun, with Castle holding out just long enough to see Kate's face scrunch up the way he liked. Then she was sucking on his bottom lip and it took everything in him to remain upright as he saw stars.

(He was never going to look at this bookcase the same way again.)

He felt himself pulsing, and his heart beat hard against his ribs. His legs were shaking and in an effort to keep himself from collapsing onto the floor, he braced his hands on either side of her, leaning against the bookcase.

Kate giggled, and pulled his head to her chest. He delighted in the sound of her own pounding heart. "'Bout time we christened the place, yeah?"

He let out a strangled half-laugh, half-groan. "I'm surprised it's taken this long, honestly."

She kissed the top of his head, lingering to smell his hair. "Mmm. Me too."

Regaining some of his wits, Castle righted himself and slid out of her. It felt cold and empty and he could tell by Kate's shiver that she felt the same. "That was… unexpected, to say the least."

He pulled his boxers and pants up and buttoned the button. Then he extended his hand to help her down from her perch.

She reached down for her shirt. "What can I say?" She slipped her arms in the holes and started working the buttons with ease. "You're the best damn PI this city's ever seen. I should have known you'd help me find what I was looking for."

It was too much. He chuckled, warmed all over, and pulled her against him in a tight bear-hug. "I love you."

"I know."

Her arms snaked around his back, his were crossed around her shoulders. He breathed her in, him shirtless and her pantsless, and suddenly felt a renewed sense of purpose. She may be kidding, still maintaining her role in their little game, but she wasn't lying about her belief in him. She really did think he was the greatest in the city.

"I wish I could come home with you, but I'm really onto something here with the case." He planted a kiss on the top of her head and then pulled back, allowing them to both finish dressing. "Don't wait up for me, but I'll let you know when I get home."

Kate nodded and finished straightening out her attire. "You're gonna find it, I just know it." She grinned broadly and Castle could almost sing. The flush on her cheeks like a shy school girl, the admiration rolling off her in palpable waves. He didn't know what he'd ever done to deserve her and her unwavering faith.

"Thank you for believing in me."

She leaned in and kissed his cheek before reaching for her jacket and handbag. "Always, babe. You know that."

He stared at the door long after she'd gone, but the echo of her confidence remained behind. Invigorated and determined, Castle sat back down at his desk and got to work.