A/N: This episode was very amusing, but I was a little disappointed we didn't get to see the wedding or even get the reception afterwards, where we might have seen some lovely, romantic slow dances. So, here's my attempt to comfort myself and add what I would have wished might have happened. I hope you like it!

Episode Tag: "Till Death Do Us Part"

"Is it more than the number of starters on a basketball team?"Castle asked softly, smiling and nodding to other wedding guests as they stood at attention while the bride and groom passed.

Beckett looked at Castle in feigned annoyance as Ryan and his new wife strolled down the aisle amidst a profusion of rose petals and applause.

"That depends," she whispered back, a teasing gleam in her eye. "College or pro?"

She caught Castle's slight intake of breath and she grinned, enjoying his gulp of dismay. He was so easy. She relaxed into the warmth of his arm as she slipped hers into the crook of his.

"See, it's like I told you. You really don't want to know."

"Well, I'm sure I could figure this out logically. Scientifically. Mathematically. You're about thirty-five, right?"

"Seriously? You're asking my age now? That's almost as bad as wanting to know my other number, Castle," she said wryly.

"So," continued her last-minute plus-one, ignoring her obvious attempt at changing the subject. "If your first time was say at age—I don't know—seventeen?—and there's been at least two a year since then—"

"Seventeen?" Beckett responded in offended disbelief, her head whipping around to stare daggers at him. Then: "Two a year? What kind of girl do you take me for?"

"Well, I don't think that's really that offensive, Beckett. Not if I add one to account for the drunken one-night-stand you likely had in college. Then, take away one—no—two for the odd dry year we all have in our lifetimes. Hmmm…take away another two for the first serious monogamous relationship. Add two, carry the three…" He pretended to cipher in his head, his eyes closed, fingers flipping up one at a time to represent each hypothetical partner.

"You finished?" Beckett asked in amusement. Like there was really some formula for figuring out something this personal.

"I'm thinking…eleven."

"Eleven?" she said, startled. "Try again, Einstein."

"A dozen?"

"No."
"A baker's dozen?"

She snorted a little in spite of herself. "No."

"A baseball team?"

"No."

"Football?"

"Dear God."

"A strike?"

"No."
"Okay, a spare then."

"Castle," she said, her voice going low in warning. The game was suddenly getting very old, and besides, their bantering had taken them all the way down the aisle to the church door. The reception was in the hotel across the street, and they followed the steady stream of wedding guests outside into the unusually warm January day.

"Odd or even?" he ventured.

"I'd say you're odd, all right," she said with an impatient sigh.

"Okay, you ready for my final guess?"

"Do I have a choice?"she grumbled.

Inside the opulent hotel lobby, they were directed to the first-floor ballroom, where banquet tables were set up on one end, and on the other, a band was tuning up for dancing later.

He led her to the place cards set at the bride and groom's table, grabbing two flutes of champagne from a passing waiter. When Castle had seated her, he took a sip from his glass, nodding in appreciation at the fine flavor.

"Seven."

"Huh?"

"Your number, dear Beckett, is most definitely…seven."

She shook her head. "Such a low guess. After all those gazinta's, Jethro, plus your foolproof formula, I figured your estimate would be much higher."

His eyes widened comically. "Did I underestimate?"

She chuckled mysteriously, downing her glass of bubbly in one gulp. Fortification, she told herself.

"I plead the fifth," she said promptly, signally for the waiter to refill her glass.

Castle looked crestfallen, because he had the feeling now that she just wasn't going to tell him no matter whether he guessed correctly or not.

"I'll tell you what, Castle," she said, glancing at his face and taking pity on him. "If I guess yours correctly in one try, I'll tell you my number. Then, for the love of God, can we end this inquisition of yours?"

"That's sounds more than fair," he said gravely, as if they were negotiating nuclear disarmament.

She studied him a moment, noting his lively eyes, his great hair, his sensual lips,his impeccable suit. How many women could actually refuse this man? How many women hadn't?

"So," she continued, pretending to take his measure just by looking at him. "I'd say…your number is…hmmm…"

Castle was literally sitting on the edge of his seat.

"You have no earthly idea how many there have been, have you?" she said in a voice lacking judgment. "I'd say you lost count about ten years ago, and you're too embarrassed to admit it. You planned to make up some arbitrary number to get me to admit my true number, because you knew I wouldn't possibly lie about something like that. Am I right, Castle? Well, am I?"

"Kate—"

"Men," she said with her earlier mild venom. "You're all the same. If I told you I lost track of the number of partners I'd had, you'd think I was a slut, wouldn't you? But if you were to tell Ryan or Esposito you'd had so many you couldn't possibly count them all, they'd be high-fiving you into next week."

"I would never think you were a slut, no matter how many there've been—"

"Ha," she said, "that's a load of crap, Castle."

He finally hung his head sheepishly, thinking he should have known better than to tangle with the great interrogator that was Detective Kate Beckett.

"All right, you found me out. I'm ashamed to admit it, but I went through a faze between my marriages, when I'd had a bestseller or two under my belt, and women were literally throwing themselves at me—I mean, geeze, Kate, high school had been very unkind to me; very unkind. I was a geek—a Trekker for God's sake. Dry year? Hell, I had a dry decade."

She nodded. "Just what I thought."

They sat in silence a moment, drinking their champagne and watching the banquet tables fill as they waited for the bride and groom to arrive after posing for their wedding pictures across the street.

"Hey, wait," Castle said, realizing he'd been bamboozled, but good. "Since you couldn't possibly guess my correct number because not even I know it, you won't be telling me yours either. Damn, lady, you're good."

She grinned, her lips at the rim of her glass. "So I've heard," she said, in that sexy way of hers when he could never tell whether she was teasing him or not. "On numerous occasions," she finished, twisting the knife. "Now, you agreed to drop this."

"But—"

"You agreed, Castle," she said sternly, brooking no further argument. "Now, let's enjoy the party. Hey, look, there's the happy couple now…"

Castle had no choice but to accede to her wishes, for, one thing he did know for sure, he could deny this woman nothing.

Xxxxxxxxxxxxx

Later, on the dance floor, Castle drew Beckett closer in his arms, loving the excuse to hold her, to smell her hair, to feel her warm body next to his.

"Castle," she whispered. He shivered as her warm breath hit his ear. "My number is five."

He grinned against her cheek. "Mine is ten," he whispered back.

He felt her answering smile, realizing that he'd played her like a fiddle.

"Well played, sir," she conceded, laying her head on his broad shoulder as their legs swayed in time to the music.

He inhaled the scent of her soft hair and closed his eyes in contentment.

THE END

A/N: Some might believe their numbers are too small here. I choose to think that in Castle's case, the media has made him into much more of a ladies' man than he is. He might have dated a lot of women, but that doesn't mean he slept with them all. And he's a great dad, worried about an impressionable daughter. I really don't see him sleeping around with her in the picture. That's my take on it, anyway. I'm sure we'll never know their actual numbers, so I think I'm covered here...

Thanks for reading! I'd love to hear your thoughts…