This one may just be my favorite because it allows for a lot of headcanon. It's also my least favorite because I have to do a lot of research (which means watching Castle, so not so bad) to keep in line with ACTUAL canon. Le sigh…enjoy!

Prompt 9 – Beckett fills a book with everything she knows about Castle. Post "Significant Others"

She buys the book on her lunch break, when Castle is at home, writing (because if he doesn't get these next three chapters done, Gina has threatened to castrate him and Kate's still using that part). She grabs a coffee and a snicker doodle from the café (Castle and Lanie would both have a fit if they knew what she was eating as 'lunch') and walks straight over to the shelf where all the nice, leather-bound journals are kept.

It takes her twenty minutes to decide which one she wants (they're all so fancy and pretty), but she thinks the maroon-colored leather and gold-edged paper is the one that most reminds her of Castle; it would do him the greatest justice. So she buys it, and—just because Castle told her to—she name drops for a little discount.

Hey! No book without a good story already written in between the pages should cost more than twenty dollars.

It comes to fifteen dollars, which she can deal with.

The book fits perfectly in her purse, right next to the 99-cent pack of gummy bears that Castle buys her every now and then as a joke (because he knows just how sweet her sweet tooth is).

After that, she grabs a burger, fries, and a shake from Remy's and heads back to the precinct to fill out more paperwork.

Thankfully, her day will end at five—unless they get a case. Which they don't. Kate thanks whoever is responsible for that particular miracle. On her way out, she calls Castle to see if he's done writing for the day and he confirms that he is, and that he's already working on dinner if she wants to join him, Martha, and Alexis.

She does.

After dinner, while Castle cleans the kitchen (he'll never let her clean so long as she's worked a full day at the precinct, no matter if it's only paperwork), she cracks open the book and wonders where to start. She doesn't have much time and she really doesn't want him to see this—see her insecurities about them—because it's really not all that important. It's really not a big deal; she just wants to prove to herself—and Meredith—that she knows him just as well as he knows her. That's all. No big deal.

So she starts with what she's learned of his childhood, stories that both he and Martha have told her—when the matriarch was not trying to make it sound overly dramatic, and more so trying to embarrass her little boy.

Richard Castle was born on April 1st, 1969.

He had perpetual diaper rash, no matter how much baby powder and cream Martha used.

He liked to streak…until he was seven. Everywhere.

He once, at 18 months old, ran out, naked, on stage during his mother's off-Broadway production of The Music Man, where she was playing Marian the Librarian. She did not break character, though everybody else did.

He has had a total of 27 nannies in a span of 14 years, none of which were American. Half of them didn't even speak English.

Knows most curses in Russian, Spanish, German, Chinese, Italian, and Indian. He picked these up during childhood.

Was suspended in first grade for peeing on a plant…indoors.

Kate smiles as she imagines a little Castle, getting into trouble as often as possible for a little boy. She remembers how hard she'd laughed when Martha told her these stories, how she'd leaned against Castle to keep herself from falling; how red he'd gone. God, he was adorable—his whole life, it seemed.

She hides the journal in her bedside table (he'd probably cleared it out for her after their first night together, because it seems that it was always hers) and smiles when he comes to her, covering her body without preamble and pressing tickling kisses anywhere he can reach, making her giggle and shriek as his fingers run over her ribs.

She forgets about the journal until morning, when she grabs it on her way out. Castle has a meeting with Paula, so they can go over his options for a possible summer book tour and talk about the renewal of his contract. He won't be in until noon, so they make plans for lunch.

She also smacks him for the three hickeys she finds as she brushes her teeth that morning, glaring at her from her reflection in the mirror. He just smiles and kisses her cheek, making her smile. She grabs a scarf and whips his ass with it before wrapping it around her neck and heading out, freshly made coffee in hand, and journal safely tucked away in her purse.

She takes the subway to work, fills out a few more things that she remembers him telling her during those lazy, post-coital conversations in bed. By the time the twenty minute journey is over, she's already filled 10 of the 150 pages of her book; they're small but that still counts for something, right?

She shoves it back into her purse as she enters the precinct, says hello to the boys, and tosses the empty coffee cup in the break room to wash later (she loves that he buys the re-washable ones) and heads to her desk, to finish off the rest of her paperwork, praying that they don't get a new case before lunch.

Again, they don't, and she has the inkling that somebody up there is looking out for her (she thinks fleetingly of her mom, but immediately brushes that thought away; no need for tears at work). It's only 11:30 when she finally signs her name on that last form and she has time to kill until she has to leave to meet him for Thai.

She takes out the journal, glancing up at the boys, who look like teenage boys cheating off of each other during a test, their eyes flicking to each other's forms as they work. She shakes her head at them as she starts to write.

144. He was sent to boarding school at age 14 after his mother got a part in a play that would cause her to travel. He got kicked out of said boarding school after only six months.

145. He's been in over a dozen boarding schools and public schools, and has been kicked out of every one.

146. He lost his virginity at the age of 16, to a girl named Eliza, whose last name he can't remember.

147. He met Kyra Blaine at the age of 18, right before they were going to go into college. Their relationship lasted three years.

Kate ignores the pang she feels at the thought of the woman who first held Castle's heart. Back before she'd even realized what her true feelings for him were, she'd almost lost him to Kyra, despite the fact that the woman claimed she was over him. Somehow, Kate couldn't see how anybody would ever just 'get over' Richard Castle.

But she's glad that Kyra did. And she's even more glad that Castle got over her.

"Kate!" She looks up to see Castle walking towards her desk, a large grin on his face as he approaches.

"Hey," she greets back, nonchalantly shoving the journal into her purse. "What are you doing here? I thought we were supposed to meet at the restaurant."

"We were," Castle confirms, "but I just wanted to drop by and say hello to the boys."

"Hey, Castle," they chorus, distractedly, still working on their paperwork.

"Please," Castle says, sarcastically, "don't look so happy to see me."

"Unlike you, we actually gotta work, bro," Esposito says, shooting him a glare.

"And unlike me," Kate adds, "you two were goofing around while I got my work done. And now you don't get a lunch break."

"What?"

"Hey!"

"Please, like nobody can see the Superman lunchbox you're always hiding in your desk, Espo. And everybody knows that Jenny is gonna drop by in, like, ten minutes to bring you a sandwich and a kiss, Ryan, so don't complain. And get back to work; Gates is glaring at you two, again."

"Montgomery wouldn't have made us work like dogs," Ryan huffs.

"Montgomery would have sat there, on your desk, and stared you down until everything was finished," Kate corrects. "Now hurry up and maybe we'll bring you some egg rolls." They give her looks and she just laughs, dragging Castle out after her.

Later, after lunch and teasing and a little making out where nobody from the precinct (namely Gates) can see them, they return to work and spend most of the time just waiting for something exciting to happen or to be let loose.

By three, Castle leaves to go start on dinner for the night, letting her know, discreetly, that they will be alone for dinner tonight, because Alexis is back at school and Martha has a night class.

She spends the rest of her time at work filling out as much of the journal as possible, eventually working her way up to the time they met, after a long list of stories he told her about raising a daughter as a single father (and just how awkward it is to explain the birds and bees and menstruation). Then she gets into the stuff that she's known since she met him.

347. He is arrogant, cocky, goofy, playful, funny, sweet, and somewhat sensitive. He can be selfish sometimes, but it's a rare occasion.

348. He is loving and insecure and loves a good story; even tells some of his own.

349. He loves to play pranks on everybody (except Gates, because he knows that she's the only one who'd actually kill him).

350. He hates cabbage with a passion. There's no explanation for it; he just hates it and wishes that there were no such thing.

351. He loves his family.

352. He loves me.

She wants to stop right there, even though there's at least a dozen pages left in the book. He used to tell her about endings and how it was difficult sometimes to know whether you should keep writing, even after a really well-punctuated line, or whether it's worth it to let it go on for a few more pages, and perhaps find an even better line.

She thinks about that as a metaphor for their relationship (sappy, yes, she knows) and how there are so many things that could have ended their relationship—hell, ended their lives—but they kept going; kept holding on. She hopes they'll have a lot of these (pages, days, years, decades) before their last line comes up. She hopes they never have to make the decision to leave each other, that they're with each other, in every way possible, until the end.

They've only been together as a couple for about eight months, but already Kate can't imagine not seeing him, not kissing him, not making love to this beautiful man for the rest of her life.

And one day she'll tell him all this; one day when she's not waiting for the other shoe to drop or wondering if they're going to make it. One day she'll just know.

But today, she thinks as she looks up at the clock, today I'm just going to focus on getting home for dinner.

She packs away the journal, makes a promise that she'll show it to him one day soon, let all her insecurities out in the open, because she knows that he'll be able to help her with them.

She thinks it's appropriate that the book ends with his love for her, because, she realizes, that's all that really matters.

Isn't it?

REVIEWS please!