Author's Note: I wasn't going to, but these last few scenes really wanted to be included in the story, so I decided they could form an epilogue. Or, if one were feeling cheesy, one could call it a Coda. I hope you enjoy.

Sing we joyous all together
Fa la la, la la la, la la la
Heedless of the wind and weather
Fa la la la la, la la la la.
-traditional

"Oh, Castle, no, you promised," Kate scolded when he opened the door of his loft. He followed her gaze to the box in his other hand, gaily wrapped in shiny red and green paper.

"I know," he said guiltily, "but I couldn't resist. It's Christmas!" He reached out and took her arm, ushering her inside.

"Yeah, but we agreed," she reminded him, stepping into the loft and taking off her coat. "Hi, Martha."

"Hello, dear," called the diva on her way through from the kitchen. "Don't mind me, I'll just be upstairs."

"Oh, that's okay. I can't stay long." Kate fixed her boyfriend with a glare as he finished hanging up her coat and turned back to her. "Castle-"

He cut her off with a kiss, looping his arm around her waist to pull her against him. She sighed, but she couldn't help responding - she could never seem to resist his kisses. By the time he pulled back, her hands were around his neck and she was panting against his lips. He smiled disarmingly.

"What brings you here, anyway? I didn't think we'd be seeing you till dinner."

"Just thought I'd stop by," she evaded, because she wasn't letting him off the hook yet. "And don't try to change the subject." She narrowed her eyes again at the gift.

"I'm sorry," he said earnestly. "I know we said no Christmas presents this year, we've only been together a few weeks, yadda yadda. But listen." He led her farther into the loft, which was elaborately decorated with wreaths, garlands, and all the accoutrements of the season. "It's Christmas Eve Eve Day, two whole days away from the main event, so it doesn't even count as a Christmas present. It's just ... a present."

"It's in Christmas wrapping paper," she pointed out, rolling her eyes. Castle gave his best puppy-dog expression, his eyes pleading with her as he pulled her down onto the couch.

"Come on, Kate," he wheedled. "Tomorrow you're leaving to go upstate with your dad, and I won't see you again until next week, and I just really want you to have this today. I was going to give it to you at dinner, but since you're here now..." He leaned over and kissed her cheek softly. "Please?" he added, silken in her ear.

She sighed and, of course, relented. "Okay, fine. I'll open it." He bounced on the couch like a little boy as she took the gift from him and began to remove the wrappings.

Inside the paper was a flat box, which she opened to reveal a spiral-bound manuscript. Printed across the front cover in an elaborate font were the words Heat Wave, by Richard Castle.

"Rick," she breathed, her mouth falling open as she carefully turned the pages, scanning the lines of music. Castle's notation software and expensive printer had turned out a beautiful musical score, lyrics and vocal lines and orchestral parts all neatly lined up on each page.

"It's only Act One so far," he said quietly, "but I wanted you to have it the minute it was ready. You can read it at your aunt's house when all that family togetherness gets to be too much." He looked a little timidly into her shining eyes. "I, I really hope you'll like it."

"I'm sure I'll love it," she said, leaning in for a deep kiss. Her heart was pounding before their lips even touched, just from the thought of finally reading the opera he was composing based on her.

"Now," Castle said when they finally broke for air, "why are you really here, Beckett? 'Just thought I'd stop by,' my Aunt Fanny. Spill."

"Um," she replied hesitantly, twisting her hands in her lap, "well, it's about our dinner plans tonight, actually."

His face fell. "You're canceling our Christmas Eve Eve date?"

"No," she said quickly, reaching up to run her fingers along his forehead, trying to smooth away the frown. "No, not canceling, just changing. I, um, I have a bit of a surprise for you too."

"Really?" His smile bloomed across his face, drawing an answering grin to her own. She loved being able to make him look that happy - it never failed to amaze her that she had that power.

"Yep, really."

"Is it a naughty X-rated surprise?" he asked hopefully, waggling his eyebrows. She chuckled.

"Sorry, babe, this one is strictly PG."

"Are you sure? Because I saw this 'slutty Santa' costume in the store and it would definitely-"

"Forget it, Castle," she said firmly. "It's just - Wait, exactly which store were you in when you saw this?" she added, fixing him with a stern look. He gulped guiltily.

"Um."

"Never mind," Kate decided. "Listen, just come to Rockefeller Center tonight at seven, okay? Bring Alexis, if she's free."

"Oh." He looked briefly disappointed. "So, your surprise doesn't have anything to do with naked ice-skating, then."

She burst out laughing. "No. No, it most certainly does not." Sobering, biting her lip, she added tentatively, "But I think you'll like it anyway."

"Hey." He slid his arm around her and pulled her closer. "I'm sure I will. Even if it is rated PG."

She leaned into his kiss again, but only briefly, before she slid her hands to his chest and gently pushed him away.

"I have to go." She glanced at her watch. "This was the last time slot Roy had before he leaves for the holidays, so I really shouldn't be late."

"Ah. Okay," Castle said, looking away diffidently.

Kate knew that he was struggling not to ask her how things were going with Roy Montgomery, with her new regime of twice-a-week singing lessons. Castle had been so careful these past few weeks not to bring it up: not putting any pressure on her, not mentioning anything even remotely related to her singing. She loved that he was being so respectful of her feelings, even though she knew it was driving him crazy wondering whether she would ever sing in public again.

He wasn't the only one, either. In the weeks after her appearances onstage for Messiah, it seemed like every newspaper and music blog in New York had put out an article asking the same question. Will we ever hear Kate Beckett sing again? they all wanted to know. She had been contacted by quite a few of them seeking comment - and when they'd gotten nothing out of her, they had tried Castle too, once word got around that the two of them were involved. Castle didn't like letting on that he was as much in the dark as the reporters were, but he did enjoy the little dance of making them chase him for answers, only to give them a No comment in response.

Many of them thought that Kate's silence on the topic was a publicity ploy, a calculated device. Of course, Castle knew that wasn't the case, and he understood better than almost anyone why Kate didn't want to talk about it, so he was restraining his frustration and waiting for her to be ready. It was so sweet, she thought, and so typical of his true nature - the one hiding behind the carefree playboy persona he affected in public - the one she had been getting to know these last few weeks, to her ongoing delight.

"Rockefeller Center at seven," she repeated, smiling softly at him. God, he made her into such a sap. "And we can come back here for dinner afterward, like we planned, just a little bit later."

"Oh, good." He grinned. "Because I already prepared the whole menu and made the dessert, and it would be a shame to let that much chocolate go to waste."

"Like chocolate would ever go to waste in this household," Kate laughed, carefully packing the Heat Wave manuscript back into its box and sliding it into her shoulder bag.

"Well, you have a point." He walked her to the door. "Oh, and Kate?"

"Yeah?" She lifted her eyebrows inquiringly at him as he took her coat back out of the closet and held it for her.

"Look up," was all he said after he had settled the coat on her shoulders and gently pulled her hair out of the collar.

She tipped her head back to gaze upward, and chuckled softly when she spotted the large, bright-green sprig of mistletoe carefully hung from the ceiling directly above her head.

"You don't need tricks to get a kiss from me, mister," she murmured flirtatiously, hooking her fingers into Castle's belt loops to pull him close. He hummed softly as their mouths met, her tongue slicking across his lips in a slow sweep.

"I know, but it's fun," he grinned against her lips, pulling her in even tighter and kissing her again.

"Later," she promised, reluctantly disengaging from him. "I'll meet you here under the mistletoe again, later."

"I'll hold you to that," he replied with a smirk. She smiled back and forced herself to turn away, pulling her bag over her shoulder and heading for the elevator.

"She didn't say where to go or what to look for?" Alexis asked at 6:59 that evening, clutching her father's arm tightly to keep from getting separated in the crush of people. Rockefeller Center was as crowded as Castle had ever seen it, and he was suddenly remembering why he didn't usually venture up to this area so close to Christmas.

"No," he replied over his shoulder as he threaded his way through the crowd. "She just said to be here at seven. Maybe she's down on the rink."

Around the perimeter of the iconic ice-skating rink, people were massed at least three deep trying to get a view of the skaters whirling around on the ice, or of the massive Christmas tree across the way. Castle craned his neck, peering around heads, scanning the ice for his girlfriend.

"Dad. Dad! Over there," Alexis exclaimed suddenly, excitement tinging her voice as she yanked on his sleeve to get his attention. He looked back at his daughter, then followed her gaze and her pointing finger to the area on the other side of the ice, beside the huge tree.

"Oh," he exclaimed. "You think? Really?"

"Yes," Alexis assented with an eager nod, "come on, let's get closer."

As they worked their way around the edge of the rink, suddenly they could hear it, getting louder as they approached: the sound of Christmas caroling.

At last Castle and Alexis reached the edge of the crowd, where a velvet rope separated the mass of people from the famous tree. At the foot of the tree, a group of choristers from the New York Symphony Choir was gathered in three neat rows, all wearing red scarves, their cheeks pink from the cold, but smiling as they sang. Lanie stood facing the group, conducting them with a wave of one gloved hand.

"Joyful all ye nations rise
Join the triumph of the skies…"

"Dad," Alexis breathed into his ear, but he had already spotted her and was standing transfixed.

Kate was in the front row despite her height, sandwiched between Judith and Doris, her smile splitting her face from ear to ear as she sang along with the group. The chilly flush to her cheeks seemed to intensify, and Castle knew that she had noticed him, though she carefully didn't make eye contact.

The chorus finished their song, nodded good-naturedly at the smattering of applause from the gathered crowd, and launched into Frosty the Snowman - much to the delight of several small children in the audience, who began to jump and dance in place, drawing smiles from the singers as well as the other onlookers.

Alexis was bouncing a little bit also in her excitement, but Castle just stood still, drinking in the sight and sound of his girlfriend enjoying herself with the choir, so carefree and happy. His face was cold, but he was beaming with pleasure, awed all over again by the strength and beauty of this woman who for some reason had deigned to spend time with him.

The peppy song came to an end, and the ranks of singers shifted; Kate stepped forward, and the others shuffled together to fill the gap she had left. At a signal from Lanie, the rest of the chorus began to croon a series of soft oohs, blending together in an accompaniment as smooth as any orchestra.

And then Kate began to sing over them.

"O holy night, the stars are brightly shining," she caroled, her clear tones rising above the rumble of the crowd and causing heads to turn. "It is the night of our dear Savior's birth."

"Ahh," sang the rest of the choir.

Alexis turned her face up toward her father. "Dad, are you going to cry?"

"Don't be crazy. I have a manly image to preserve," he muttered, nudging her with his elbow, blinking fast and hard.

"Long lay the world in sin and error pining," Kate sang, "till he appeared and the soul felt its worth."

"Ooh, ahh," the choir continued.

"Your secret's safe with me," Alexis whispered, and slid her arm around Castle's waist. He hugged her close, never taking his eyes off Kate.

"A thrill of hope, the weary world rejoices. For yonder breaks a new and glorious morn."

The whole chorus burst in exuberantly with "Fall on your knees" and Castle thought he just might.

After the song was done, the audience burst into applause again, and Kate resumed her place among the sopranos. The group sang several more songs, and then they were finished, smiling and waving at the crowd as they began to disperse.

Castle had seen several people in the gathered crowd snapping pictures with their phones, and he had no doubt that the news of Kate's little solo would be circulating on the 'net within minutes. He didn't mention that to her, of course, when she finally finished saying her goodbyes to the other singers and made her way over to him.

"Kate! That was awesome," Alexis enthused, throwing her arms around Kate as soon as she was within reach. Kate squeezed the girl back and smiled with genuine pleasure.

"Thanks, Alexis. It was fun." Then she turned her face toward Castle, her smile turning a little bashful. "Christmas caroling is always so much fun."

"Best surprise ever," he asserted with fervor, kissing her lightly, and then more deeply when Alexis let her go. He paused and pulled back to look into Kate's eyes, hoping that his face conveyed everything that her singing and her courage made him feel; and then he couldn't resist pressing his mouth to hers again, tasting her sweet smile.

Kate pressed up eagerly into him, her nose cold against his cheek, making him yelp. She pulled back again and laughed a little.

"Wimp."

"Get a room, geez," Alexis put in, pointedly turning her back on them. Castle snickered, but Kate was blushing and looking down, so he took pity on both of them.

"Let's get you out of the cold, Kate. And Alexis, isn't it time for you to get to Paige's house for your sleepover?"

Together they fought their way through the crowd to Fifth Avenue and, miraculously, found the town car that he had ordered earlier. Despite the heavy traffic, it only took a few minutes to get to Alexis's friend's house, and the girl hugged them both quickly before climbing out of the car with her backpack.

As the car headed back toward Castle's loft, he pulled Kate closer and kissed her again, but she disengaged after only a moment, blushing and muttering "Not in the car."

"Oh please, I'm sure this driver has seen a lot worse," he grinned, but he acquiesced, just taking Kate's hand and holding it between both of his.

At the loft, they chatted easily while Castle finished the meal prep that he had begun earlier. Almost everything was ready, the entree needing only a few minutes in the oven to warm up while he dressed the salad and poured the wine. They sat at the dining table, eating and talking and exchanging the occasional heated glance.

When the meal was finished and the second glass of wine polished off, he said, "Ready for dessert?"

"Ooh," Kate said, putting a hand to her stomach. "I'm stuffed. Let's take a few minutes to digest first."

So he got up to clear the table, and as usual Kate rose to help, and as usual he tried unsuccessfully to tell her to sit and let him do it. Instead they cleared together, loading the dishwasher and putting away the rest of the wine for later.

Castle was running water into the pots to soak them when he heard Kate's sultriest voice calling him.

"Castle, I need you over here for a minute," she said, velvety soft, and he turned from the sink to see her standing by the front door. For a moment he thought in dismay that she was going to leave, but then he remembered the mistletoe. His heart leapt, and he couldn't stride across the room fast enough.

"Hey, you," he breathed as he pulled her into his arms. She smiled up at him, her eyes dark.

"Hey," she responded, and kissed him hotly. He groaned, pressing her closer against him as their tongues twined together.

"Castle," Kate gasped, pulling back after a minute or two of heated kissing.

"Yeah?" he panted, chasing her lips again.

"Let's go to the bedroom and have dessert," she murmured, her eyebrows arching suggestively.

"I thought you wanted to wait," he smirked.

"I'll wait for the chocolate," she replied, sliding her hands down his chest to curl her fingers in the waistband of his pants. "Right now, you're my dessert."

An hour or two later, after spending some time in the bedroom, then going back to the kitchen for the chocolate mousse that Castle had made, then back to the bedroom, and then taking a lengthy shower together, it was time for them to reluctantly say goodbye. Kate got dressed and combed out her still-drying hair while Castle sat on the bed in his boxers, watching and pouting.

"I don't want you to go."

"I know, but this was the plan," she reminded him, ruffling his hair affectionately on her way through the bedroom to retrieve her shoes from the study. "I'm leaving with my dad first thing in the morning, so it's better this way, remember?"

"Yeah, yeah," he grumbled, following her out to the living room. "It seemed to make sense at the time, I guess."

"Don't sulk, babe. You'll have a nice Christmas with Martha and Alexis, and I'll be back in time for New Year's." She went to the closet to retrieve her coat. "I'll call you from Aunt Theresa's house if I can. Tell you what I thought of Act One."

His face lit up. "Promise?" He took the coat from her and held it for her to slide her arms in. "I loved your surprise too. It was so great hearing you sing again."

"Oh." She turned back to him, suddenly shy again, blushing, smiling. "Really?"

"Of course." He drew her closer, buttoning up her coat. "And that was really smart, Christmas caroling. It's low-pressure and fun."

"Exactly." She smiled up at him, gratified. It was the same reasoning that had convinced her to agree to the caroling when Lanie suggested it. "That's what I thought too. And thanks for not pushing me about it, Castle. You've been so careful not to ask, and I-"

"Hey," he said gently, smoothing her hair back from her face. "I knew you'd say something when you were ready."

"Yeah." She bit her lip deliberately. "Maybe when I get back, I'll give you a private serenade."

His eyebrows went up, amusement and pleasure blossoming in his eyes. "Well, I'll certainly look forward to that." They both chuckled softly, and he pressed his mouth to hers again one more time as she reached over to open the door.

Reluctantly, they separated, and she stepped out the door, giving him one last smile before she left.

She was just getting off the elevator at the ground floor when her cell phone rang.

"Castle," she half-laughed, half-scolded into the phone. "We just said goodbye a minute ago."

"I know," he agreed, "but I just wanted to make sure you know that I miss you already."

"Don't be so melodramatic." She rolled her eyes, but she was smiling as she walked toward the subway. "You'll be fine. Go sit at the piano, work on Act Two."

"Yeah." She could practically hear him perking up. "Yeah, I'll do that."

"Okay. I'll talk to you soon, babe."

"Right." He sighed a little. "Okay, have a good trip. Drive carefully."

"I will. And don't stay up too late. Remember, Santa can't come until you're asleep."

He chuckled softly. "I won't. Merry Christmas, Kate."

"Merry Christmas, Castle."

A/N: Thanks for reading! I hope you enjoyed this story. If you did, you might also enjoy the sequel, which is just one chapter, titled Root Position. You can find it on my profile page.