Based on a prompt from thealways47stuff on Tumblr. I'm gonna go a little against it and set this in Season 2. The prompt is at the bottom of this story.
"Jojo," Kate calls as she rushes around the kitchen, making coffee and toast, "come on, babe; time to get ready for school!"
Her eleven-year-old daughter appears from her bedroom, dressed but still rubbing the sleep from her eyes. Her hair, which rival's her own mother's curls, is unbrushed and mussed, bangs falling into her face. "There's no school today, Mom," she says, as her mouth opens in a wide yawn.
"What?" Kate says, turning to her with a frown. "It's Monday, isn't it?"
Johanna Isabella Beckett nods. "Yeah, but it's also Faculty Development Day," she informs her mother and Kate curses under her breath. Damn public school. "I heard that," Joey says, smirking. "You owe me a dollar." That smirk is as infuriating as the twinkle in her baby blue eyes.
"I swear you have your grandmother's bionic ears," she mutters as she hands the girl a glass of orange juice and a plate of slightly charred toast.
Joey wrinkles her nose at it. "I'd rather wait for Castle's breakfast," she says to her mother.
Kate is almost offended until she looks at the blackness that covers half of her own toast. "Can't really blame you," she sighs. "But drink your OJ, alright? No use in wasting it." The young girl nods and sips at the cup while Kate pours her first coffee of the day. She didn't make a lot, knowing that her unofficial "partner" would show up with her usual Starbucks order and a bear claw in tow. She takes out her phone and texts him so he knows to bring Jo's usual order, as well.
Kate wonders how it is that her daughter had bonded so fiercely with the incorrigible man-child so quickly after they met, even going so far as to try and convince Kate to accept his numerous date proposals. She hasn't yet given in though. But she knows that Johanna is not likely to stop anytime soon.
Though the young girl did take Kate's side last summer after Castle decided to look into her mother's murder against her wishes. But the second he came back, she was all about forgiveness and became his best friend again like nothing had even happened. In fact, if it weren't for Joey, Kate and Castle might never have reconciled.
He texts back a smiley face and she can't help but reflect it.
"What are you smiling at?" Jo asks and Kate looks up to meet the big blue eyes, always so inquisitive and intelligent. They make her think of the girl's father, who is still a blur in Kate's memory.
It was during a layover in Las Vegas that she met the man at the airport bar. She shouldn't have been drinking, but long flights made her antsy and the bartender barely even glanced at her fake ID, anyway. She figured a drink would relax her for the remainder of her flight to New York. She had two hours until it left, anyway.
He was the only other patron, downing shots of whiskey like his life depended on it. He sat on the other side of that bar, his shoulders slumped and his shaggy hair obscuring most of his face, but not that frown. She'd moved down the bar to sit next to him, struck up a drunken conversation that somehow led to the creation of the little girl sitting right in front of her, sipping from a Coca Cola glass full of juice.
The only thing she remembers of that drunken night is the floppy hair and the man's light blue eyes, which Johanna Isabella had apparently inherited from him. Everything else—except for those adorable dimples—came from Kate's side of the family.
"Finished!" Joey's voice snaps Kate out of her daze and she smiles brightly at the girl who'd brought her out of the rabbit hole that was her mother's case one too many times. Jo was the reason that Kate's father, had quit drinking and why Kate's decision to join the NYPD was solidified. Even if she couldn't solve her mother's case, she wanted to make the streets safer for her baby girl.
"Okay," Kate says, standing. "Go brush your hair and then we can go."
Joey groans. "Can't you just put it in a braid?" she asks. "Please?" She gives Kate those big puppy dog eyes, which are completely unnecessary this time, but usually work in getting the older woman to do the younger's bidding.
"Fine," Kate says, finishing her coffee. "Go get the stuff and brush your hair through. It'll take less time if it's neat."
The girl nods and rushes off, leaving her empty glass and Kate rolls her eyes, picking it up. As she washes the cups, she thinks about the Las Vegas man who fathered her child; the man who gave her the gift of the truest love she's ever experienced. Sometimes, she wants to track him down, to find him and thank him for what he's given her; even to share that love of a child with him, because he's her father and totally deserves to know what it feels like to share that bond. But she knows it's been too long. He might not accept Joey and…and Joey might not accept somebody who's been absent from her life for the last eleven years.
Besides, Kate thinks as Joey pads back in with the brush, bobby pins, and a ponytail holder, they're doing just fine without him.
"Jojo!" Castle exclaims as Kate and her young daughter walk into the precinct.
"Castle!" she squeals as she runs full force towards him, as fast as her legs will take her. Castle catches her midair and lifts her, effortlessly, above his head. She giggles and Kate can't suppress the smile that spreads over her lips as he brings the girl down to rest on his hip and smiles over at her.
"Good morning, Detective Beckett," he greets, nodding to her as he picks up the cup he'd already set on her desk. "One Grande skim latte with two pumps of sugar-free vanilla," he says, handing it to her.
"Thanks," she says, taking the cup from him and sipping at it with reverence. He really makes the best lattes.
"And, for the little Beckett," he says, smiling down at Joey as he reaches for the other cup, "hot chocolate with peppermint and cinnamon." It's another trait she and Castle share; the inexplicable taste for the two spices combined. Kate usually wrinkles her nose at it, but it makes Joey happy, so she makes sure to always keep them on hand.
"Thanks, Castle!" Joey exclaims, taking a sip and practically purring. Kate chuckles and rolls her eyes.
"And there's a bag of bear claws with your name on it," he tells them as he places Johanna in his chair and gets to helping her with her hat and scarf. Kate plucks up the brown paper bag on her desk—which literally reads, 'Beckett,'—and reaches inside for a chocolate glazed bear claw, handing it to Joey once she's out of her jacket. The child takes it with a wide smile and bites into it. Kate smiles at the chocolate mustache she sports as she bites into her own plain, sugar-coated donut.
Castle gives Joey the same smile as he walks into the break room, his eyes sparkling with affection for the young girl. It's the same look he gets when he looks at Alexis—who's another pretty big fan of Joey—and it softens Kate's heart for him just the tiniest bit. Joey catches her look and gives Kate a knowing smile as she takes another large bite from her donut. The detective sticks her tongue out and the girl giggles.
"Mini Beckett is here!" a voice says and the two Becketts turn in the direction of Esposito's voice as he steps out of the elevator with his partner. Joey immediately jumps out of her seat and leaves her breakfast on the table in favor of running towards her other two favorite guys in the world.
"Uncle Espo!" she cries. "Uncle Ryan!" The former catches her and the latter presses a kiss to her cheek.
"Good morning, princess," Ryan says.
"Good morning," she chirps in return, showing her dimples as she smiles brightly at them. Espo tucks her under his arm like a football and carries the giggly girl to his desk, where he perches her on the edge and she laughs again. "My hot chocolate," she says, pointing at Kate's desk. Ryan plucks her breakfast up and takes a bite out of her bear claw as he hands her back her cup. "Hey!"
Ryan laughs and gives her the donut before making his way into the break room, where Castle already has three hot cups of coffee freshly made. He hands one to Ryan by way of greeting and the shorter man thanks him, taking a sip. As he does, his eyes study Castle's face, his head tilting slightly as he swallows.
"You know," he says, "if I didn't know any better, I'd say that Joey is your daughter; not Beckett's."
Castle snorts. "How do you figure that?" he asks.
"Well, the dimples, for one thing," Ryan says. "Beckett doesn't have dimples."
"Maybe her parents have them," Castle says, shrugging, "or Joey's father." He still gets bitter just thinking about the man that refuses to be in their lives. Kate never told him anything about the douche that got her pregnant, but he's certain that there must be something seriously wrong with him if he doesn't want anything to do with a great kid like Joey.
"Your eyes, too," he says. "They're the same shade as Jojo's and Beckett definitely doesn't have blue eyes."
"Again, that could come from her actual father," Castle replies, shaking his head. "What are you getting at with this?"
"Nothing." Ryan shrugs. "She just looks a lot like you is all; it's kind of funny."
With that, the Irishman leaves, sipping on his coffee. Castle frowns at that and tries to put the ridiculous thought out of his mind as he grabs his and Espo's coffee and heads out of the break room. The Hispanic detective thanks him as he places the coffee on his desk and he makes a face at Joey, who makes one back at him. He laughs, but can't help but notice that she looks remarkably like Alexis when she was that young. Even her nose is…
Castle shakes his head. It's impossible, though. He's only just met Beckett in March of this past year. Besides that, she's about a decade younger than him and he hasn't been with anybody that young since…
"Have you ever been to Las Vegas?" he asks, suddenly, as he sits down in his chair at her desk, sips his coffee casually as he waits for her answer.
Kate's green eyes widen at the question and that little wrinkle of confusion appears between her eyebrows. "Once," she says, "why?"
"When was that?" he asks. "And did you do anything scandalous?" He wiggles his eyebrows playfully as he whispers the question to her, mindful of the young ears about ten feet away.
Kate rolls her eyes but can't suppress her smirk. "Well," she says, "you know what they say about Vegas, don't you, Castle?" He laughs and nods.
"I have a few stories of my own," he reveals.
"I bet you do," she snorts, wryly, into her cup. He makes a face and she laughs; the sound is like music to his ears. He's always loved her laugh.
"Seriously, though," he says. "There was this one time, at the airport…I was, uh, I was going to pick up Alexis in Los Angeles, from her mother's and, uh, I met this woman. Nice, young, drunk as all hell." He laughs and Kate rolls her eyes.
"Do I want to hear this?" she asks, the clear indication that she doesn't in her voice, but Castle needs to know. So he nods.
"There's a point to this," he tells her. "Trust me."
Kate spares a glance over at Esposito's desk, where Joey is being entertained by her partners, giggling and showing off those adorable dimples of her. She turns back to Castle and nods for him to continue.
"She told me that she was waiting for a layover," Castle goes on. "So was I. I had just written Hell Hate No Fury, too and that bombed, so I was a bit…depressed. I decided to go to the bar and drink it all away—or try to, at least—and—"
"Oh my god," Kate interrupts, suddenly, her face turning beet red. "Oh god, no."
Castle's eyes widen at that and realization dawns over his own face as his mouth gapes and he points at her.
"You!" they hiss in unison.
This will be no more than a three-shot, but I would like to hear your thoughts on it so far. Is it worth continuing? Let me know!
Prompt: Kate Beckett has a daughter which was conceived during a layover in Las Vegas on her way back home from Stanford. Kate was drunk at the time and only remembers the man's blue eyes. Ryan mentions one day how much her daughter looks like Castle and throws everything into chaos. The prompt was for Season Six, but I changed it to Season Two because I like the angst of it a lot better.