A/N: Just in case you haven't read it, this chapter contains minor spoilers for a certain scene in Richard Castle's Heat Rises.

Kate had forgotten all about scheduled Castle's poker night with the fellow mystery novelists that evening. The men usually had these gatherings every few months when their schedules miraculously coincided and she knew Rick looked forward to them, but he never minded if she hung around during the events. She had a feeling he enjoyed having 'the real Nikki Heat' around to show off to his buddies, even though she made sure he received the death glares she sent him any time he attempted to speak of her as a prize.

The fellow authors usually found their relationship more amusing than anything, always teasing Castle about life imitating art and how he should abandon the mystery genre for romance novels. The older men would tend to flirt with her as well, aiming to get a rise out of Castle and throw him off his game – which always worked – and as she walked down the hall of his floor, she realized she was looking forward to seeing the batch of writers again. But when she inserted her key to unlock the front door, she was met with an unfamiliar poker attendee, Alex Conrad, attempting to make a hasty getaway at the same time.

"Sorry, Detective Beckett," he apologized at the near run in, but his brow was furrowed and his eyes were downcast as if he was intently trying not to look at her.

"Hey, is everything okay?" she asked in light concern. The amateur novelist looked a little frazzled and she had a bad feeling about what had gone on inside the loft with Castle and his buddies.

"Yeah, I just - I don't think I should have joined in on poker night," he explained tightly, scraping a hand through his already tousled hair, appearing thoroughly embarrassed.

"That bad?"

"Could have been worse." He shrugged. "I simply believe my real reason for being invited here was to be taught a lesson by Mr. Castle. Stay away from his muse," he chuckled before bidding Beckett a goodnight.

Kate huffed at the behavior portrayed by grown men, particularly one stupid man, and heaved Castle's front door open, strode inside ready to teach him a lesson of her own.

"Richard Castle," she said his name like she would when he was in trouble, like the time she had arrested him, and the laughs from the living room immediately died down.

"Oh. Hey… honey," he answered sheepishly when she came to stand in front of him at the poker table.

She quirked an eyebrow at him. "Guess who I just ran into?"

His eyes widened and she could tell he knew she was onto him and what he had done.

"Umm, well," he stumbled through bits of a sentence. "I don't know, could have been anyone-"

Kate stepped around the table, settled comfortably into the seat Alex Conrad had previously occupied, and picked up his abandoned set of cards. Castle was talented at poker, but she was a worthy opponent and if he wanted embarrassment, she would give it to him.

"Don't mind if I join in, right guys?" she addressed the other two men at the table with a seductive smile and a deliberately slow blink of her lashes.

Lehane and Connelly quickly nodded their assent while Rick glared at her from across the table.

She was going to demolish him.

Kate waited until Connelly was finally out the door to saunter up behind Castle, lace her arms around his neck.

"You are ruthless," he huffed, defying his statement by dropping his chin to his chest, brushing a kiss to her wrist.

"I was just showing you how it feels," she hummed into the back of his neck, waiting until his hand reached around to touch her hip to relinquish her hold on him. "You shouldn't have done that to Conrad."

"Done what?" he questioned innocently, turning around to lean back against the door in an act of nonchalance. "It was just some friendly hazing."

Kate narrowed her eyes on him. "To hear him describe it, it sounds like someone was trying to teach him a lesson."

"What?" he laughed a little too loudly. "Why would I want to do that?"

She stepped closer, her crossed arms a barrier between them. "Because you didn't want him to spend time with me."

"That is completely-"

"True," she supplied and Castle went strangely quiet for a moment, the playful cluelessness falling away and a frustrated expression contorting his face instead.

"Yes. Fine. It's true, I'm jealous," he admitted, purposely not looking at her. "There, I said it. I – I want you all to myself, and to have you spending time with another man, another writer, doing things that only you and I do together, that upsets me, and if that makes me the petty, jealous boyfriend, so be it. Guilty as charged."

The lasting hints of irritation drained from her, leaving empathy in its wake. She sometimes forgot Castle was the kind of man who needed reassurance. Under all the feigned arrogance and false devil-may-care mannerisms, he had his moments of self-doubt and a fair share of trust issues. She had always painted herself as the unsteady one in this relationship, but in times like these, it occurred to her that they were equals in most areas – the good and the bad.

"Actually, I kind of think it's sweet," she sighed softly.

His eyes cleared, brow arcing upwards from its creased position in gentle surprise.

"You do?"

"I do," she nodded. "But Rick, you have to know that there's no one else, not for me. No man, no writer, and I don't want you ever thinking otherwise," she pressed, allowing her hands to reach for his waist, slipping up to splay along his torso. "You're it for me. There's never going to be anyone else."

"Well," he murmured, pleasant delight etching into his features, coloring his eyes a warm cerulean. "That was worth being embarrassed by Nikki Heat in front of Lehane and Connelly."

She grinned, rocking forward on the balls of her feet when he caught her by the hips and leant forward to kiss her.

"So no more writers shadowing you?"

She shook her head.

"I am a one writer girl."

He nuzzled his nose in her hair. "Good because even if Conrad is my mentee, I don't like him bringing you muffins," he grumbled and she rolled her eyes, pinched the soft skin of his ear between her fingers.

"Ryan's brought me cronuts before and you've never had a problem with that."

"That's different," he said matter-of-factly. "Ryan doesn't want to sleep with you."

"Neither does Alex," she countered coolly. "Unlike you, he was not attempting to get in my pants while learning about police procedural work."

"I was never-"

She pinched his ear harder and he whined, lifted out of her grasp.

"Don't even deny it, Castle."

"Fine," he grunted, rubbing scornfully at his ear. "I wanted to sleep with you from the day you walked into my book party."

She smirked at the begrudging tone of his admission and brushed her lips over his in reward before whispering, "Me too."

Ever since she had essentially given him permission to ask her again, Castle had been attempting to plan the perfect proposal. He needed to get it just right this time. No room for screw-ups or bad timing.

She had the upcoming Saturday off and Rick had organized a dinner for the weekend at her favorite restaurant. It would be small and intimate, just like she had always wanted. He had rehearsed how the night would go in his head multiple times, and he actually thought everything would go perfectly according to plan.

Until Mike Royce was killed and any ideas of engagements and marriage were immediately put on hold as he saw her heart crumble at the sight of her dead friend.

Montgomery had her off the case by the very first day, yet they still ended up on a plane to Los Angeles together to investigate the murder themselves hours later.

"Two bedrooms?" she asked curiously once they had been led to their suite in the extravagant hotel he hadn't been able to resist treating her to. They may be in LA for murder, but they could still indulge in a few of the city's perks, right?

Castle shrugged as he sat their bags down on the pristine white couch in the middle of the room. "I just figured… After what happened with Royce, if you wanted to be alone…"

A small smile flickered across her lips as she drifted towards him.

"That's sweet," she murmured on a quiet sigh, curling her fingers absentmindedly around the collar of his shirt and smoothing her thumb over the fabric. "But I don't want to do this alone, too."

"Then you won't," he answered quickly. "Do you want me to downsize us to a single room, because I can. I-"

"Castle," she chuckled, shaking her head softly at him. "This is fine. We'll use the extra bedroom as a headquarters for our investigation."

"Good plan," he conceded with a nod. "But can we still go to that couple's massage later today because-"

"Castle. We're here for justice."

He sighed mournfully as she swiped a kiss from his lips before turning on her heel and striding into their new 'headquarters'.

Maybe LA wouldn't be as fun as he had hoped.

Montgomery had effortlessly caught on to their plans within the same afternoon and by nightfall, the forbidden quest for justice had Beckett exhausted. She was laid across the couch, her head on his thigh while they stared mindlessly at the reality show playing on the television.

"I can't believe that I'm never going to see him again," she murmured suddenly, picking at the material of his jeans with her fingers.

That sadness she had been repressing since the day before, since witnessing Royce's body at the crime scene, was slowly seeping out of her, spreading along them both like a suffocating blanket, and he knew it was normal, healthy even, but he hated seeing the grief course through her. It was his instinct to try to help.

"You know what I thought when I first met you," he asked quietly, combing his fingers through her hair even though it tended to annoy her.

"Hmm?" she replied without moving.

"That you were a mystery I was never going to solve," he admitted with a soft smile, tracing the shell of her ear with his thumb. "Even now, after spending all this time with you, after… everything we've been through together, I'm still amazed at the depths of your strength, your heart, and your hotness."

She turned her face into his knee, nipped teasingly at his patella through his jeans.

"You're not so bad yourself, Castle," she said, rotating onto her back and staring up at him with a small grin and dark eyes. "Hey, I have an idea."

Kate heaved herself up from the cushion of his lap and off of the couch. Castle watched her trot across the suite towards the bar in the corner.

"Kate," he said with a warning in his voice.

She waved him off as she returned to the sofa with a bottle of tequila in hand. "Calm down, Castle. Just thought we'd play a little drinking game."

"Hoping to reenact a certain scene from Heat Wave?" he smirked.

"Or inspire a new one," she threw back, sitting cross-legged beside him and filling two shot glasses with the shimmering brown liquid.

"Considering I am in need of a good sex scene for Heat Rises, this could definitely work in my favor," he grinned, but she rolled her eyes.

"No one said anything about this ending in sex," she quipped, but Castle huffed at her in amusement.

"Doesn't it always between you and I, Detective?" he asked with a wiggle of his eyebrows that made her chuckle. "So what kind of game are we playing here?"

She settled her pursed lips against her fist for a moment in contemplation and then snatched the Vanity Fair magazine that was resting on the coffee table. "There are these standard questionnaire things in here," she explained as she flipped through the pages. "We can ask each other questions. You take too long to answer or decide to pass on a question, you drink."

He nodded thoughtfully. "Interesting. But I'm not in the mood to get drunk, not when we have to be up early tomorrow," he added, attempting to be nonchalant about it, because in all reality, it was her he didn't want drunk. Not tonight. Not when she was still mourning Royce and feeling defeated in her investigation.

He knew if she indulged too heavily in the alcohol, it would only leave her miserable and that was the last thing he wanted.

"What do you propose as a substitute?" she inquired, toying with her untouched glass and skimming over the questions in the magazine.

"Clothing," he supplied with ease. "For each question you fail to answer, you lose an item of clothing."

"Like strip poker?"

He shrugged. "Call it what you will."

She hummed her approval. "I can't see a real downside to this."

"Exactly."

Kate read the list of questions aloud, and they started out easy enough – Name your favorite hero in literature. Who's your favorite poet? What is your motto? - "Really? Who has a motto?" he demanded incredulously, but she was quick to reply with the phrase she had taken from her mother and he ended up losing his plaid shirt first. But the questions began to grow a little too serious for their lighthearted game at times, both of them using the option to pass more than once, and within half an hour, she was in only her underwear while he was left in nothing but his socks.

"What is your ideal dream of earthly happiness?" she asked quietly, keeping her eyes downcast to the page in her lap.

"You first," he murmured, already slipping his socks from his feet because he knew his answer to this one, and he had a feeling she did too.

Kate wordlessly set the magazine down on the table and drew her panties down her legs. He held her by the hips when she rose over him on her knees, capturing his face in her hands and slanting her lips over his.

"This," she whispered into his mouth as his hands roamed her naked skin. "This, this, this."

Castle tugged her down and they both maneuvered their bodies into a horizontal position on the couch. He felt her let go of the burdening weight Royce's death had bestowed upon her and give into the hungry rhythm of their bodies instead.

"This is definitely going in the book," he panted between kisses and she nipped hard at his bottom lip, but he still felt triumphant when her lips spread into a grin.

A/N: Thank you Laura for your brainstorming brilliance on this one.