So when the last and dreadful hour
This crumbling pageant shall devour,
The trumpet shall be heard on high,
The dead shall live, the living die,
And Music shall untune the sky.

-John Dryden, "Song for St. Cecilia"

New York Symphony Hall rang with the cacophony of dozens of instruments tuning and warming up, singers practicing their scales, and the exuberant voices of people who hadn't seen each other in several months. Outside it was a sunny but cold Monday in December, but in here it could have been any day, any season, almost any century.

"Kate!" cried a cheerful female voice, and principal violinist Kate Beckett looked up from her music stand to bestow a wide smile on her friend, the alto section leader.

"Hey, Lanie!" She stood up and hugged the other woman tightly. "How've you been? Good summer?"

"Not bad. Busy. You?"

"The same," Kate nodded, glancing around the hall. "It's good to be back."

"Yeah." Lanie leaned in and lowered her voice. "Is it true about Perlmutter? The rumors are flying."

"It's probably safe to say that some of the rumors have some truth in them," Kate evaded, but then broke under her friend's glare and whispered, "Rehab."

"Ooh!" Lanie gasped, patting her chest. "I knew it. The man had been looking like crap all last season."

Kate grimaced. It was true, but she wouldn't have chosen to phrase things quite so bluntly when it came to the symphony's beloved but crotchety longtime conductor.

"Hey, there's another rumor going around," Lanie added, nudging her friend. Kate bit her lip and avoided her friend's eyes, knowing what was coming.

"Yeah, that one's true too."

"Really?" Lanie practically squealed, grabbing Kate's arm so hard that she winced. "Richard Castle is going to be conducting us for this concert? The Richard Castle?"

"The one and only," Kate nodded, sighing a little, wondering how much crap she was going to get for this. Lanie was one of the only people in the world who knew just how highly Kate regarded the work of Rick Castle, musical composer extraordinaire, society darling, and renowned playboy.

"Did you meet him yet?" Lanie demanded in a stage-whisper, and Kate nodded reluctantly.

"Just briefly, yeah."

Fifteen Minutes Earlier

Howard Grainger, the symphony orchestra's general manager, had called Kate into his office and she walked in with nervous butterflies tickling her guts, wondering if the rumors were true - that she was about to meet, and work with, her favorite composer. His rock opera Flowers For Your Grave was one of Kate's absolute favorite shows, ever; she had seen it at least half a dozen times during its lengthy Broadway run.

But from everything she had heard about the man himself, she wasn't so sure she really wanted to meet him. If he was as much of a jerk as the rumors claimed, maybe it would ruin the magic.

"Oh, Kate, good," Howard said as soon as she appeared in the doorway. "Maestro, let me introduce you to your concertmaster, Kate Beckett. Kate, Maestro Castle."

"Enchanté," the other man said smoothly, turning from the window to bestow a dazzling magazine-cover smile on her. His hand was warm when it enveloped hers for a lingering handshake, and she didn't miss the way his blue eyes flickered appreciatively down and back up her body. "It's truly a pleasure," he purred.

Kate pressed her lips together and just barely restrained herself from rolling her eyes. The man appeared to think that all he had to do was smile and, what, her clothes would just fall off? Maybe that worked with ambitious airhead opera singers, but Kate Beckett was a professional.

"Nice to meet you, Maestro," she said in her best crisp, businesslike tone. "The rehearsal is scheduled to begin in twenty minutes, as I'm sure you know."

"I do," he agreed, still smiling, appearing unfazed by her cool demeanor. "I'll be ready, not to worry. And please, call me Castle. Everyone does."

"Kate," Howard cut in, "I hardly need to tell you how lucky the symphony is to have had Mr. Castle so graciously step in on a last-minute basis. It's very generous of him to give us his time and talent, and of course he hasn't conducted this kind of thing before, so any assistance he might need - anything at all - I'll expect you to accommodate him."

"I'm sure Kate will be very accommodating," the composer oozed, and this time Kate couldn't hold back an eyeroll, though she did turn her face away from Howard so that he wouldn't see it.

"It's going to be fine," she assured her boss with a calm nod. "Everyone out there knows what they're doing, and I'm sure it will all come together."

"It will," Castle agreed, "and anyway, it's not rocket science. It's just Messiah." He paused for a moment, then, and looked at Kate again. "Wait a minute," he said slowly, "you said Beckett?"

"Yeah," she sighed, knowing what was coming. And it did.

"You're Johanna Beckett's daughter," he exclaimed, the realization lighting up his eyes. She sighed again and nodded.

"I am." She waited for him to turn awkward and fidgety, the way people did when they suddenly remembered what had happened.

Much to her surprise, though, Rick Castle remained smooth. His expression became solemn and sincere. "I was really so sorry to hear about her passing," he said quietly. "It was a great loss."

Taken aback, Kate had to blink hard a few times before she could manage a "Thank you."

"Well, let's get to it," Howard broke in with forced cheer. "Kate, I'm sure you have some final prep, and Maestro Castle will be right out as soon as we've finished the paperwork."

"I just met him for a minute in Howard's office," Kate told Lanie. "Nothing much to report yet. We'll have to see how things go." Taking her violin out of its case, Kate stuck it under her chin and plucked the strings briefly, checking the tension.

"Look at you, playin' it cool," Lanie teased, and Kate groaned and changed the subject.

"Listen, Lane, about Perlmutter - the management is going to spin it as some kind of illness, so lips zipped, okay?" She picked up her bow and played a quick arpeggio. She loved the way the notes resounded in the open space of this beautiful old hall, even with all the other ambient noise.

"Oh, don't worry about me. I got nothin' riding on that. The gossip mill will churn on without me just fine." Lanie scowled and added, "The first-rehearsal pool, on the other hand…."

"You guys still do that?" Kate shook her head in amusement, putting her violin down again. "Perlmutter had gotten way too predictable."

"He really had," Lanie agreed with a laugh. "Remember the year when I won by betting on Since By Man Came Death? They all said I was crazy, but the man freakin' loved that one. I got almost a whole new spring wardrobe from my winnings that time."

"I guess you and your fellow chorus members will have to find another form of entertainment," Kate teased, but Lanie shook her head.

"Nope. The pool's still on. You want in? Ten bucks and your guess of which movement he'll start the rehearsal with."

Kate thought about it. For a first-time conductor of Messiah, the odds were pretty good. "It's gotta be either And The Glory or Hallelujah, doesn't it?" she mused. Lanie nodded.

"Those are the favorites, for sure. The first one, and the most famous one."

Eyebrows drawing down thoughtfully, Kate reached for her purse. "You know what, put me down for For Unto Us."

Lanie looked surprised. "Really? You got some insider information here, or what, girl?"

"Nope. Just a hunch."

"Okay," Lanie said a little skeptically, accepting the ten-dollar bill that Kate handed over. "Well, we'll see soon enough."

Rick Castle had watched with a slight smile as Kate Beckett walked out of Howard's office. The few brief words they'd exchanged had left him intrigued, and he was already looking forward to working with her.

As he tried to turn his attention back to the paperwork, he felt his nerves beginning to reassert themselves. Castle was by nature a self-assured kind of guy, but he was out of his element here: conducting a major symphony orchestra and chorus, with music that he hadn't composed, and classical music at that. He knew that Howard was looking at him with some skepticism, no doubt thinking that Rick Castle didn't know his Handel from his Haydn. And Howard wouldn't be the only one thinking that kind of thing here today.

Castle was determined to prove them all wrong. He had spent the whole weekend studying the Messiah score: behind his desk, on his couch, at his piano. He had taken copious notes and felt he was about as well-prepared as he could hope to be, under the circumstances.

Accepting the last-minute invitation to guest-conduct this concert had been a no-brainer. The request, or desperate plea, had come from a guy on the orchestra's board of directors to whom Castle owed a favor, and then his agent had chimed in with a very definite opinion on the matter. "It'll be great publicity, Ricky," Paula had said, pointedly leaving unspoken the rest of that sentence, which hardly needed to be said: he hadn't written any new music in over a year, and anything that kept him in the public eye - short of breaking any laws or starring in any unsavory tabloid scandals - was to be seen as a good thing.

Not that he'd needed much more convincing. He was bored, and tired of sitting around waiting for a new inspiration to strike; and, although he wouldn't have admitted it to almost anyone for fear of sullying his image, he actually really liked the music of the Baroque era. Who didn't love Handel's Messiah, anyway?

And now that he had met the concertmaster, he was even more glad that he had agreed to take this gig. Kate Beckett may have refused to respond to his flirting, but that only made him more determined to get to know her better. And she would hardly be able to avoid him this week; not only was she the concertmaster, but Howard had told him she was also the accompanist and assistant leader for the chorus rehearsals. There would be six rehearsals this week, followed by three performances over the weekend; plenty of opportunity to get to know the music, the orchestra, the chorus, and the principal violinist in particular.

So: a chance to get out of his house and out of his own head; to perform some glorious music that was very different from his usual bread-and-butter; and to spend time with the gorgeous and fascinating Ms. Beckett. Yes, overall, Castle was very much looking forward to this week.

"Drinks after the rehearsal?" Lanie asked as she tucked Kate's ten dollars into her pocket.

"Sure. If you win the pool, you're buying."

"Back atcha," Lanie laughed, and then they both stopped talking and exchanged glances as Howard appeared from the rear of the house with Rick Castle at his elbow. The orchestra and chorus slowly quieted as the two men moved up to the conductor's stand.

"Good afternoon, everyone," Howard boomed in his press-conference voice. "It's nice to see everyone back again for another holiday season. Now, I'm sure some of you may have heard that our beloved longtime conductor, Sidney Perlmutter, has unfortunately been taken ill. We all send him our best wishes and hope he'll be back making beautiful music with us again soon."

What a load of horse crap, Kate thought, but she kept her expression neutral, setting an example, knowing that many of the eyes in the room were on her. As concertmaster - and long since accepted as Perlmutter's right-hand woman and the person who kept rehearsals running smoothly - she was ever conscious of presenting the right image.

"In Sidney's absence," Howard went on, "we're very fortunate to be graced with the talents of a very special guest conductor. I'd like to present to you all Maestro Richard Castle."

Applause burst out, along with speculative looks being tossed back and forth. Very few of the musicians in the room looked surprised; Kate could see that the rumor mill had been active.

"I'll let you get to it, Maestro," Howard concluded, and stepped away.

Castle ascended onto the conductor's platform, put an armful of sheet music and notepaper onto the music stand, and nodded to the assembled groups. "Thank you very much. It's a pleasure to be here," he said easily, "and to have the opportunity to work on this beloved music with you. I'm hoping that at least a few of you have done this piece once or twice?" He winked, and polite laughter bubbled up.

"Now, I know what you're thinking," he went on. "Half of you are thinking, look at this guy, does he even have a clue what he's doing? and the other half are thinking, will he sign my chest? And the answer to all of you is yes." He grinned cockily. More laughter, much of it genuine this time. Kate shook her head, but even she couldn't contain a small smile.

"It's true that I don't have a whole lot of experience conducting this type of music, but I think we can all muddle through it together. Okay?" He looked around the room, still smiling, and Kate noted with interest how he already had more than half of the orchestra nodding and smiling back. Well, the stories about his charisma had obviously not been exaggerated.

"Good," he said cheerfully. "For today I'd like to try to run through everything without stopping, and then we can really get into whatever needs to be worked on starting tomorrow. Now," he went on, and looked over at Kate a little uncertainly, "has the chorus been warmed up yet?"

"Backstage," Kate said, as the chorus members nodded. Castle gave her a quick grateful smile, and she felt herself flushing slightly. Damn it, she was not responding to his attention. Stupid.

"Good. Thank you. Let's have the orchestra tune up, then."

Kate signaled the first oboist, and the orchestra began to tune as the last few chorus members made their way onto the risers and found their places.

"Okay," said Castle at last, when Kate nodded to him that the orchestra was ready. "We have trumpets and tympani today, right?"

More nods, and the trumpet players held up their instruments.

"Great. So, to begin with, I'd like to run through the three movements that require trumpet, not counting The Trumpet Shall Sound because our bass soloist isn't with us today," Castle went on. "But before we get to that, I'd like to start out with For Unto Us, number twelve."

Kate pursed her lips and chewed on the inside of her cheek to keep a straight face, watching a ripple of whispers and nudges go through the chorus members. She saw Lanie standing at the front of the alto section, pointing a narrow-eyed glare in her direction.

"Did I miss something?" Castle asked, pitching his voice toward Kate. Her stand-mate sat up a little straighter, but Kate merely shook her head.

"No. But before we begin, you might tell us which movements you intend to do for this concert."

"Right! Right, sorry. Um." He shuffled through the papers and books on the music stand. "Okay, everyone, so we're going to do all of Part One, skip most of Part Two except for Lift Up Your Heads and How Beautiful Are The Feet, and of course, Hallelujah." He looked up with a grin. "Can't miss that one! Then in Part Three, we have the soprano solo and the bass solo, but we won't be doing those first two choruses. Just Worthy Is The Lamb and Amen."

"Thank you," Kate said, as the orchestra and chorus members scribbled on their scores. She rose briefly and called across the assembled group, "If anyone has questions about the program, come and see me at the break."

"Everyone ready for number twelve?" Castle asked, as Kate resumed her seat.

At her nod, all of the violinists and violists lifted their instruments to their shoulders and held their bows at the ready. The cellists and bass players lifted their bows as well. The wind section sat up straighter, instruments poised at their mouths. The chorus members stopped rustling pages and looked up, holding their books at chest level. The concert hall stilled, an expectant silence gathering as every eye in the room settled on Rick Castle.

He tapped his fingers against his leg briefly, finding the tempo, and then lifted his hands. He gestured four quick beats, the fourth like an indrawn breath that ran the length of the room, and the music began.

Author's Note: This story is obviously very much AU, and I know that the premise won't be everyone's cup of tea, but I hope you'll give it a chance anyway. As always, please do let me know what you think. I love hearing from you.

My outline currently suggests that this will run approximately 15 chapters.

Title of this story was provided by my 9-year-old daughter, who says that it represents "the universe, which is everything, and sound, which is music." Enough said.