Disclaimer: The only part of Castle that I own is the TV on which I watch the show.

A/N Some of the firsts will be canon, some will not.

It's after midnight, and the loft is quiet. Rick Castle is in his office, leaning back in his chair with his feet on his desk, staring gloomily into his Scotch. She turned him down. The cop—correction, detective—actually turned him down. Well, that's a first. Okay, not exactly a first, but a first in his adult life. When was the last time it happened? He takes a sip and ruminates. Must have been in college, before he had money? Because he sure as hell hasn't been turned down since then, not even when the women, whoever they are, find out that he has a daughter and is raising her on his own. In fact, at least in the short term, that's been really good date bait. He's Mister Sensitivity. And short term is ideal, because he's not interested in long term. Done that, twice. Even if it wasn't that long-term, the marriage. Either marriage.

It rankles. Kate Beckett turned down his dinner invitation, even after he helped solve a murder. You'd think she could have gone out for a drink with him, at least. But what did he get? A handshake, for God's sake. A handshake and "It was nice to meet you, Castle." Nice to meet you. The brushoff that a dweeb gets. Not him. He rattles the ice cubes in his glass. The crystal tumbler set him back $80, and the booze? Hmm. Sixteen drinks in a bottle, bottle cost $300, so this nightcap is about $19. He'd have spent a hell of a lot more than that taking her out, even to a bar. Unless she was one of those wine spritzer types. He doubts it.

What type is she, anyway? Not his, that's for sure. Tough. Very tomboyish. Plain pants and shirt. That short hair, no shape. Probably cuts it herself with nail scissors. No makeup. No jewelry to speak of except that watch that looked like it had seen better days. Oh, and some little chain around her neck. So her turning him down is really no big deal. Except it is. Because holy shit, she's sexy. Unbelievably sexy. That little mole under her eye. He'd like to get her out of those very plain pants and very plain shirt and undoubtedly very plain underwear. No, not plain. Maybe very slutty underwear. She turned him down, but when he said, "Too bad, it would have been great," she said, breathing right into his ear without actually touching him, "You have no idea." And when she walked away from him she strutted, with a teasing sway of her ass that he hadn't see before. Oh, yeah, she definitely wears slutty underwear.

And another thing: she does nothing with it, but she's beautiful. And something else, something very else: she's smart. Wildly, fascinatingly smart.

Realizing that he's a little hungry, he goes to the kitchen and fetches a jar of roasted peanuts. On his return trip he looks out the window. It's been pouring for the last hour, and the sidewalks are empty. Not even a cop. When she was a rookie, maybe she walked a beat out there. He might have passed her in the street and not noticed her. Huh.

With his feet planted on the desk again, he goes over and over the past few days. She's gotten under his skin, that Kate Beckett. Detective Kate Beckett.

One hot member of the NYPD.

Packing heat.

Bring on the heat, baby.

His feet land so hard on the floor that he can feel it in his spine. He opens his laptop, creates a new file, and starts typing as fast or faster than he ever has. When daylight comes through the open bookshelves, it startles him. Sun? The rain stopped? And what the hell time is it? Oh. The computer screen tell him it's 6:30 a.m. Shit, he has to get moving, make sure Alexis is awake, make her some toast, pour her a glass of OJ—and he needs coffee. He trots through the living room and goes halfway up the staircase; he can hear movement in her room, so he needn't go up. His mouth feels like Rommel has been waging desert warfare there. The sands of El Alamein have reached his eyes, too. After slicing a bagel and starting the coffee, he goes to his bathroom to wash his face and brush his teeth. That's better. He's surprised he doesn't look worse. On the other hand, there's a reason he looks this good: he's about to turn his professional life around, big time. He knows it, absolutely knows it.

Much as he adores his daughter, he pays only half attention when she chatters on about how glad she is that her braces are off and she never has to see the orthodontist again and something about a science project.

"Dad!"

"No need to shout, Alexis, I'm three feet away."

"The science field trip. Can I go?"

"Of course you can go, my little Marie Curie."

She shoves a piece of paper and a pen in front of him. "Then sign this, please."

"Boston? It's in Boston?"

"Yes, Dad, hellloooooo. I just told you that."

"Sorry, sweetheart, I didn't get much sleep." He scrawls his name on the bottom of the form and pushes it across the counter to her. "Have a good time."

"I'm not going right now, you know. It's for next weekend."

"Right."

"Dad? I'm going to school now. You should go to bed."

"Good idea. See you later. Dazzle everyone in the ninth grade all day."

"I'll try." She kisses him on the cheek, and vanishes through the front door, her backpack and braid swinging.

If it were manly, he'd skip to his laptop. He does, anyway. It's time to email the Mayor. His buddy, the Honorable Robert Weldon. Time to cash in the chips that he's been holding for some time. Time to propose that he be permitted to shadow Detective Kate Beckett, the model for the detective in the new book—the new series, count on it—for which he wrote the first two chapters this morning. Nikki Heat, of Heat Wave. If the book is to be as good as it deserves to be, he needs to do a lot of research. On-the-job research. It'll be an enormous boost for the profile of the NYPD. How could they not let him do it?

"Are you kidding me? You're letting him do this?" Beckett is in her Captain's office, fuming. One shredded vestige of self-control away from stomping.

"I'm not the one," Montgomery says soothingly, as if trying to placate a child in his kindergarten class who's about to go into full-tantrum mode. "The one is the Mayor. The other one is the Commissioner. I'm the one who's way below those ones. This department gets a lot of black eyes, many of them underserved, and this will change that. And that makes everyone happy."

"Everyone but me," she says with a bite. "Sir." She takes a deep, uncalming breath. "And he's a total jerk." She's aware of Montgomery's eyebrows shooting up, but she goes on, undeterred. "The ten-year-old kid who lives next door to me is more mature than he is."

"That may be, but Castle helped solve your case. And may I remind you, he has a string of bestsellers?"

"Don't count on any more. The latest book sucked. He killed off his hero. Idiotic move."

"Ah, so you read it?"

Yes, she'd read it. Stayed up until one o'clock this morning to read it. He'd given her an advance copy, even signed it, which she has to admit was nice of him. She'd told him so, too, but of course that was before she'd discovered that he'd stolen files from her desk. Still, she's not about to let the Captain bait her. Forget it. "Only because he gave it to me. All right. Let him hang around for a week or two. He'll probably be bored by then anyway, and if he's not, I'll put him out in a plastic recycling bin, very appropriate for a writer who's starting to recycle his plots."

"I hope your recycling bin is a lot larger than mine, Beckett. I'm a tall guy."

Son of a bitch, there he is, standing in the doorway, smirking. Well, she's damned if she's going to apologize for telling the truth. "Might need a second one to accommodate your ego, then, Castle." She brushes by him, with a parting, "You have to go fill out a mountain of paperwork or you can't so much as look cross-eyed at me."

"Oh, I'd never look cross-eyed at you. It would destroy the view."

It's so tempting to smack him one. How long is she going to have to put up with this crap? She hopes he writes fast. He must, right? Considering how many books he's already produced. He should be out of here by Memorial Day, at the latest. She will memorialize the occasion with a sensational bottle of wine, which she'll drink at home, soaking in a bubble bath while she reads a good book. Not one of his.

Over the course of the next few weeks and an assortment of cases, he constantly says inappropriate things; fails to follow even simple instructions; butts in during interrogations; brags; never does a lick of paperwork, and is frequently reckless. On the plus side—though it's not that much of a plus since he drives her freaking insane—he is an off-the-wall thinker, frequently with good results. But she and her team had done very well without him and will continue to do so once he gets his ass out of here. That's something that she'll confess to no one, especially Lanie, that she thinks he has a spectacular ass. That's not enough of a plus to offset the minuses, either. She's just giving credit where it's due. Making an observation. She's a Detective, and she's trained and paid to observe. That is all.

And then today, about a month after he started shadowing her, they caught a case in which a city councilman had been shot, rolled up in a rug, and left in a dumpster. Beckett had had to inform his widow, who was also the mother of their little girls. It's the worst part of her job, and it never gets any easier, especially when it involves kids. Each time she's mentally right back at the front door of her house on a cold January night, with an NYPD Detective telling her and her father, in a voice devoid of any emotion, that he's sorry for their loss. "Sorry for your loss," the emptiest phrase in the English language, and she has to say it dozens of times year. When she and Castle had gone back to the car after speaking with the councilman's widow, she'd sighed. She must have looked as dejected as she felt, because he'd said, "You okay?"

She'd been so taken aback that she'd come back with, "Yeah, why?"

And he'd said, quietly, "Can't be easy, breaking that kind of news."

He'd said that. Utterly straightforward. A simple, compassionate summation, and he'd meant it. Well, that's a first, she'd thought. She hadn't known he had that in him. He'd surprised her so thoroughly that instead of replying, "It is, thanks," she'd said, "Well, thanks for not making it a joke." She regrets it, in a way. He'd been decent—more than decent, kind—and she'd sort of thrown it in his face. Well, not really. She'd expressed her gratitude while letting him know that he hadn't behaved well in the past. Thinking it over now, sitting in her apartment after a tough day, she has to hand it to him for handling the situation so so well.

Because what he'd said next was, "Hey, I'm a wise ass, not a jackass."

"Maybe you're not an asshole after all, Castle," she says, raising her glass of wine to him in her empty living room. She takes a sip. Maybe it wouldn't be so horrible if his research weren't finished by Memorial Day. Maybe he could stay until the Fourth of July? Independence Day. And suddenly some unbidden voice in the back of her mind tells her that she might not want to be so independent, after all.

TBC