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

A/N There's a little side trip into M territory in this chapter. If you want to skip it—I promise you will miss no plot points—stop reading at "My turn, Kate" and resume at "Eventually they recover."

It's almost nine on Saturday morning. "I'm going out for a run," Kate says, appearing in the kitchen in leggings, sneakers, and a fleece jacket.

"But it's so cold," her partner-in-every-way says, holding a flour sifter in one hand and a large wooden spoon in the other.

"I love to run in this weather. That's the reason I'm going." No, it's not. Liar, liar. She hopes her leggings are fireproof.

"When you come back you can have a cookie. A lot of cookies."

"You trying to fatten me up, Castle?"

"No. You're perfect. Besides, I know you. You'll never gain an ounce."

She squeezes his cheeks. "Atta boy!" And then she kisses him. "That's the answer I wanted."

"The only time you'll have any extra padding on you is when you're preg—" Oh, shit. How had he said that? Even though it's true. Even though he dreams of her being pregnant. He has lots of dreams of that, ever since she agreed to move in.

She's frozen in place, and her eyes are huge. "Castle?"

"Um."

"You're dripping butter onto the floor from that spoon. See ya."

And now she runs. She runs to the elevator but decides to run down the stairs instead. She's not running because of what he said. She's not. Really. She's not. It's just that she can't wait to get to the craft store, which opens in three minutes—about the length of time it will take her to walk there. If she runs she can make it in under two. She'd told Castle that she was going out for a run, so she she's running. She didn't say how far, so it's not a fib, exactly. She finished the embroidery this morning while he was showering, and she's pleased with it. All she needs now is the trim, which is the point of her craft store visit.

She finds exactly what she needs almost as soon as she walks in.

"These are nice ones," the cashier says, ringing up the sale. "Are you decorating your kids' stockings?"

Kate's red cheeks are not the result of her two-minute dash in twenty-two degree weather. "No. Not yet. Thank you." Not yet? Not YET? Maybe she'll go for that run, after all. She shoves the small bag in her jacket pocket and takes off.

Notyetnotyetnotyetnotyet. It's on a loop in her head as she makes a loop around Battery Park.

When she comes through the door the smell of gingerbread cookies puts her back in the kitchen with her mother. She follows her nose to the kitchen, where baking racks are already filling up with edible trees, wreaths, Santas, snowflakes, stars and what looks like—what is—an NYPD car, except that Castle has frosted it red and green instead of blue and white. She picks it up. "Did you make this with one of the new cookie cutters from the Tinsmith of Tudor Village?"

"I did! Didn't he do a great job?" She's back! Not that he'd thought she wouldn't be. Maybe a little bit of his doubting, terrified mind had. Definitely had, after what he'd said before she ran out.

"He did," she says, biting off the trunk and front wheels of the gingerbread squad car. "So did you. This is delicious."

"Thank you."

"Gonna take a shower. I'm all sweaty."

"I love you being sweaty."

"I know you do, but I don't, at least not this way. Maybe I can get sweaty again later. For you." She pops the rest of the cookie in her mouth and sashays towards their room.

"Breakfast will be ready when you're done," he calls out to her.

"Thanks."

She showers quickly because she wants to sew the trim on the boxers, which have been nestling in a stack of tee shirts in her chest of drawers. Perched on the hamper, she sews the trim on quickly, wraps the boxers in some tissue paper, and returns them to their hiding place. "There," she says as she closes the drawer.

On her way to the kitchen, she stops short. There's something about seeing him in his apron—Cookie Monster in a Santa hat—and the memories of her mother baking at Christmas that push her to make a decision.

"You got something in the oven, Castle?" she asks as she plops onto a stool at the counter.

"What?"

"I said, do you have something in the oven?"

"Right. No, I did. They're all done."

"Because you know, when I was about to go for a run, you started to say something about when I'm pregnant. Something in the oven, people like to call it."

He has a plate of cinnamon toast in his hand and almost drops it. "Kate. Listen, I'm so sorry. I didn't mean—"

"It's fine. It is. I'm not ready to have something in the oven yet. A couple of years from now, though." She drops her eyes and then looks back up, her voice lighter. "You gonna give me that toast before it gets cold?"

He thrusts the plate at her and turns around to the sink so she can't see that he has teared up. He takes two mugs from the cabinet and fills them with coffee, by which time he's brought his emotions under control. "Here you go," he says, and pushes the mug across the polished granite surface to her. Then he reaches into his jeans pocket, takes out his phone, and types something. "Done," he says, slipping it back and taking the stool next to hers.

"Done?"

"I just made a note for this date in 2014, when we can talk about what you said."

She smiles and squeezes his thigh. "So, you want to get the big tree for the living room today, don't you?"

"Yes. Mathias set some aside for me. He knows exactly what I like. I'm going down there at six."

She reaches for a piece of toast. "Why not go now, while it's light?"

"It's too crowded at this time on a Saturday. Plus I really like going there when it's dark. Very ethereal. I don't suppose—." He looks tentatively at her. "Would you like to come?"

"Sure. Sounds like fun."

Sounds like fun. Wow. Angel choirs are massed on the staircase. Bells are chiming. Carolers are at the door. Nat King Cole is at the piano, singing "Chestnuts Roasting on an Open Fire." She wants to pick out a tree with him. "Good. I'm glad." He calls on all his self-discipline to sound calm, since he's in fact euphoric. Beside himself, elated, over the moon, ecstatic. "I've got some writing to do now, okay?"

"Okay. I'll put this stuff in the dishwasher. And then I'm meeting my dad and we're going to the Javits Center, remember?"

"Sorry, did you tell me? I forgot. The Javits Center? What for?"

"The annual baseball card convention, Castle, catch up. We're going to get some autographs. Dad's bringing the ball I caught at the first game he took me to. Nineteen eighty-seven. Big Dave fouled if off and I caught it. He's going to be there and I want to get it signed."

"Big Dave?"

"Dave Winfield, Castle! Dave Winfield. Six feet six. Right fielder for the Yankees. Hall of Famer."

"Got it," he says, pushing himself off the stool. "Don't forget to wear your Yankee shirt. And hat."

"Already on the bed so I can put them on. I'll be back by five."

It's just after sunset when she comes home. "Look, look, look!" she cries as she rushes in his office. "Big Dave signed the ball! And he even wrote 'To Kate. One of New York's Finest' on it, can you believe it?"

Castle looks over his laptop at her. "A Hall of Famer with excellent taste. You'd better put that away before it flies out the window or something."

"Are you kidding? I'm locking it in the safe."

"You want to change out of your Yankee gear into something warmer? It's almost time to get the tree."

"I'll be ready in ten minutes."

An hour later they're walking into the lot, each chewing a large, soft pretzel that they got from the vendor on the corner. "There he is," Castle says, pointing at his friend in the sky blue knitted hat.

"Wow, he's almost as tall as Big Dave."

When they reach him Castle makes the brief introductions. "Kate, I'd like you to meet Mathias. Mathias, Kate."

"God kveld," she says, extending her hand to the tree man.

"God kveld," he replies, shaking it and smiling widely. "Kan du Norsk?"

"Nei. Jeg snakker bare litt Norsk."

Castle is agape. "Geez, Kate. What are you, a mini UN? What did you just say?"

She shrugs shyly. "Just good evening. Then he asked if I speak Norwegian and I said no, only a little bit."

"You could have fooled me," Mathias says happily. "Your accent is almost perfect."

"She fools me all the time," Castle says. Kate surreptitiously elbows him, hard.

"Takk, Mathias. And since you're burning to know, Rick, I said 'thanks'."

"You're welcome. Are you two ready to pick out your tree?"

"You bet," Castle says. "I look forward to this all year."

They end up with a Frasier fir, just over ten feet tall, and secure it to the roof of the Mercedes with a series of bungee cords. Castle has a red flag to tie to the end of it. TREE ON BOARD.

"Really?" She raises an eyebrow.

"Had it since Alexis was three. Great, isn't it?" Castle pays Mathias and reminds him that he'll drive him to the airport first thing on Christmas Eve so that he can wake up on Christmas morning with his family in Ålesund.

Getting the tree upstairs in the freight elevator and then setting it up in the living room takes three men: Castle, the off-duty doorman and the porter, both of whom are well-paid for the work.

"Are we decorating this monster tonight?" Kate asks later, while they're having pasta and salad.

"No, no," Castle cautions, incautiously waving a forkful of rotelle. "You have to let the tree settle overnight. Let it get used to being indoors."

She wipes her mouth and sets her napkin neatly to the left of her plate. "So the evening is ours?"

"It is."

"Glad to hear it."

"You have plans?"

"I do." She runs her eyes up and down him. "My plans involve undecorating. A person. Specifically, you."

"You're singing my song," he says, dropping his own napkin on the table and standing up.

"And what song is that?" She's already partway to the bedroom.

"Oh, I'm sure you'll recognize it when you hear it. You're going to make me sing, aren't you?"

"I am. You coming, Castle?"

The instant they're in the room she has him up against the wall. "I'm going to undecorate you," she whispers, "one button at a time." The top of his shirt is already open, so she has only five to undo, stopping between each to kiss him, the kisses growing increasingly provocative. They're both breathing heavily. "One to go," she murmurs as she pulls his shirt off him. "The most important one." She pushes the metal button through the buttonhole at his waistband, unzips his Levi's and tugs them down his legs. He manages to step out of them and kick them aside, grateful that he's wearing neither socks nor shoes.

"My turn, Kate," he says, grabbing her hand and spinning her so she's now against the wall.

"Let me see your boxers first. I didn't get a chance this morning." She puts him at arm's length and grins when she reads the message on the bright red underwear. "IT'S CHRISTMAS. IT'S GOOD TO BE ELFISH!"

"Thank God you don't have any buttons," he says, running his hands under his soft jersey top. "Don't think I have enough self-control in reserve for that right now." He reaches around her back with one hand and unfastens her bra. "I'll just take care of this one little hook and eye."

Her bra joins his clothes and her shirt on the floor as Castle unties the drawstring on her pants, which are also soft jersey. "Oh, my," he says, sliding them off her with one hand while the other caresses a hip and then moves to the inside of her thigh. He continues to caress her, and when he moves to her pubic bone and strokes two fingers across her she moans. "Speaking of buttons, Kate," he says seductively, "I think this one is ready to go."

He's right, and so are his magic fingers, which tease and twist and flick and curl and press as she clenches around them. "Oh, God," she gasps against him several minutes later, "what a way to go, Castle. Can you carry me to the bed, please?"

"With pleasure," he says, scooping her up, then depositing her gently in the middle of their bed.

"C'm here," she says, pulling him down next her before rolling on top of him. "Time to finish undecorating you." She peels down his boxers and, with an assist from him, gets them all the way off. "Nothing elfish about this," she says, wrapping her hand around him. "Not elfish at all." She leans forward and slides slickly over him again and again, her nipples brushing his chest with each pass, until neither one can bear it any longer. In one fast, sleek move he's inside her, and they establish a hard, syncopated rhythm. Her heels are digging into the small of his back as she tries to drive him impossibly closer. When he lifts her ass just the right way to change the angle of his thrust, she comes violently and vocally and soon after so does he.

Eventually they recover. "Told you I'd get sweaty for you later," she says, her leg draped over his and her head on his chest.

"Totally worth the wait." He kisses her on the temple. "Are you humming?"

"Nope, singing."

"Singing? Whatcha singing?"

"Your song."

"My song?"

"Yeah, don't tell me you don't recognize it."

"Sing it a little louder."

She does.

"Aha! 'Jingle Bells'."

"Almost."

He moves so that he can look into her eyes. "What do you mean by almost?"

"Look under your pillow."

He has to roll over to do it, but he manages, and finds a small square package wrapped in tissue paper. "What's this?"

"You decorated a little tree for me, so I decorated a little something for you." She sits up, the sheets draped at her waist. "Aren't you going to open it?"

"I thought you said no presents."

"I repeat, you gave me a tree, so I'm giving you something. Besides, it's not so much a present as an addition to your holiday wardrobe. A decoration."

He tears the paper off and unfolds the shorts. "JINGLE BALLS!" He traces the red-and-green letters with the tip of his index finger.

"Told you it wasn't quite Jingle Bells."

"But this is my handwriting. This is amazing. And it's all hand-made. Who did this?"

"I did."

"You? You, Kate Beckett?"

"I, Kate Beckett, with my own hands."

"The same hands that a few minutes ago were—"

"I hope you're not going to say something indecorous, Castle. My Granny taught me how to embroider."

"She teach you the decorous art of forgery, too?"

"No, that was Mark, the grunge rocker. Don't tell my dad."

"Oh, I wouldn't dream of it. But wait, I need to look at these more closely." He scoots over and turns on the bedside lamp. And then he starts to laugh.

"You like them?"

"I love them. Especially the accoutrements, the tiny jingle bells you sewed along the fly."

"I got those at a craft store around the corner. I don't think that was the manufacturer's intended use."

"Maybe not. But you know what? These are the best Christmas boxers of all time. And I should know. I have an unparalleled collection and it's now the Everest of collections." He kisses her in a manner befitting someone who has become the proud owner of Jingle Balls boxers. "Thank you."

"You're welcome. I think you'll probably be able to wear them only in here. Might get unwanted attention if your pants are jingling."

"Fine with me, Kate. And you know what?"

"What?"

"You can ring my bells anytime."

"I should hope so."

TBC