They end up going.

Castle wanted to, and honestly, even though their relationship hadn't worked out, she still considers Will a good friend. One who came through for her when she needed him to, heck one who'd been shot as she pursued her case. Time heals a lot of wounds (her sojourn to DC casts a new a light on Will's decision to go to Boston), and more than anything else, the ring on her finger lightens all sorts of loads from her shoulders. It's also nice to dress up once in a while, put on a fancy dress and do her hair (Alexis and Martha fluttered and helped and generally got excited as she got ready). Plus there was Castle in one of his expensive suits, the light blue shirt and navy blue tie she'd picked out for him really bringing out his eyes, his hair curling over just so, and she'd had a hard time keeping her hands off him as the limo he'd ordered drove them over.

The reception hall is packed, abuzz with people and talk, and she slides her fingers through her husband's, curling them around his broad digits, seeking comfort. He gives her a slight smile, those blue eyes warm like the ocean, and she finds her equanimity again.

"Champagne, ma'am? Sir?"

She takes a flute from the waitress, hands it off to Castle, and then takes one for herself. The hall is decked out in subtle and understated colours, very elegant. She sees a few people she recognises- over there is Will's younger brother, whom she'd met briefly when she'd gone home to see his parents. She can tell a bunch of his FBI buddies are hanging out it one corner, that traditional G-man haircut a dead giveaway every time. His parents are already seated at the main table, talking to some other older folks, probably also family.

"Not much like ours, huh?"

He whispered into her ear, and she couldn't help but smile. The meal after their wedding had been much smaller, it was true. Just the five of them, seated around the dining table in his Hamptons house, the catering company that Martha and Alexis had organised at the last minute delivering a simple but delicious meal.

It had been perfect.

"I like ours better, babe."

"Me too, Mrs. Castle, me too."

It had been months now, and it still sent a thrill up her spine when he called her that, when she still struggled to believe sometimes that they'd made it, past all the obstacles and crazy hurdles in their way, past themselves and their own baggage. She lightly touched the cool gold of her ring on her finger with her thumb, sliding over it, pressing it against her flesh.

"Kate, you came."

She whirls at the sound of Will's voice, behind them, and Castle turns with her, his broad chest to her back. Will is wearing a tuxedo and his hair is slightly longer than she remembers, but otherwise she can see he's still the handsome guy she used to date (and yet the frisson of attraction she used to feel is completely absent). Next to him is his new wife, short and pixie-like, honey-blonde hair curled carefully into waves, blue eyes that are almost the same shade as Castle's. She didn't know how well they'd be received but this woman is smiling in genuine happiness and welcome.

"Will, of course. Congratulations. To both of you!"

"Thank you. I'd like to introduce you both to my wife Lena. Lena, this is Kate and her husband Rick."

"Pleasure to meet you."

"Likewise."

Her accent isn't thick, but it is noticeably German, and then Castle is taking over, doing his whole charming-author shtick, and she gets a moment alone to talk to Will.

"Thanks for coming, Kate. Honestly, we're glad to have you both here."

"I didn't know…"

"I get that. But it's a long time ago, and water under the bridge. And we were friends for quite a while before we started dating. I told Lena all about it, and she was more than happy to have you here."

She smiles softly, glad to have her fears allayed.

"How did you meet? What does she do?"

"It was when I stationed in Europe- I went to attend a course on new software and technologies the Germans were developing for law enforcement agencies, and she was the company rep and programmer teaching the course. I asked her out for a drink after the course and then…"

"Here we are."

"Here we are, indeed. But of course, congrats for you and Rick, Kate."

"Thank you."

They looked across at their respective spouses, Castle bending over so he could hear whatever Lena was telling him animatedly. Something about how much she loved his books, even the German translations.

"I kinda had an inkling, you know, back at the precinct when we worked that kidnapping and then the mobster case."

"You did not."

"You just…you kept him around, Kate. I figured you liked him. I'll admit I didn't expect it go this far, even if you were a big fan of the books."

She shrugged, the straps of her dress staying tight to her shoulders thankfully.

"He's good for me."

"Yes, he is."

He looked back over at his wife as he spoke, his features softening in a manner she'd never seen before. Will Sorenson, head over heels. It was nice to see.

"Love looks good on you, Will."

"You too, Kate. Now if you'll excuse us, we have to go say hi to my boss."

She nodded as he gracefully extracted himself and Lena from the conversation, gliding them over to where an older couple stood, the man's posture ramrod straight as an Assistant Director of the FBI should.

Castle came back over to her, sliding his hand around her waist.

"I still remember when you offered to get into a dick-measuring contest with him, by the way." She murmured into her champagne.

He choked on his.

She laughed, not able to suppress the bubbling brook of hilarity at his bulging eyes and reddened face.

"I- that- you weren't, I mean we weren't…"

"It's alright though, Castle." She patted his arm gently. "You won, after all."

He gave up, staring at her ruefully before relaxing his shoulders and letting his embarrassment fade.

"Not my finest hour, but yes, I'll take it. I'm the one here married to you, after all."

"I mean, you're an idiot, but you're my idiot."

She tugged his hand, bringing them over to the seating chart, so they could see where they were seated and who with.

"Not that you knew it back then, threatening to have me thrown out the precinct every few weeks."

"Can you blame me? You were more of a jackass back then."

They drifted away from the seating chart, still in their own little bubble, the rest of the reception carrying on around them.

"I'm just glad you didn't really try very hard. Couldn't have you end up sad and lonely captain of the precinct, and me going broke, unable to write, Alexis living in LA…"

"Buck up Castle, your subconscious is very melodramatic. Though I'm still annoyed that you took me out on a date which was a stake-out instead."

"Not you-you, dream-you."

"Still, it wasn't very nice."

He nodded mournfully in agreement. She'd teased the details of his little sojourn into dreamland out over the next few days after the wedding, intrigued by the world he'd imagined (Lanie? Pregnant? She'd almost threatened to split him in half with a scalpel when she'd heard that little titbit). But she couldn't really quibble with the broad strokes of the picture he'd painted- she probably would be quite alone, behind her walls, married to the job if he hadn't come along. Been persistent. Kept showing up. Made her fall in love with those baby blues.

They'd arrived at the table now, but she didn't let go off his hand as she circled the table looking for their names. It was empty otherwise, they were the first to arrive. There. She saw the two names, side-by-side. Mr. Richard Castle. Mrs. Katherine Beckett.

She'd thought long and hard about changing her name once they signed the official marriage license and filed the paperwork. She'd almost done it. Her mother had done it, and she knew Castle would support her either way (as he had, in fact, said later on). Now, still, she thought about it getting it done, about making them one unit so visibly like that. But she also liked being called Beckett (even he still called her Beckett, most of the time). The name was burned into her, part of her identity, part of who she was, especially at the precinct. She couldn't give it up. Not yet.

She smiles at him as he pulls her chair back for her, brushing a kiss against his cheeks before sitting down. He takes his place next to her, where he should be, while the MC starts asking the rest of the attendees to start taking their seats so the meal can be served and the speeches begin. They watch Will and Lena make their way to the front table, hand-in-hand.

"Do you think we looked that happy?"

"I think we looked a thousand times happier, Kate."

She didn't stymie the smile that curled over her lips.

"Well, I know I won too. I'm glad we made it, Castle…"

He picked up his flute, tinging it against hers gently.

"…besides, as the only person to know what was inside those trousers when they would have dropped, I definitely won."

He choked on his champagne again.

A/N: Actually I don't think they would end up going, but I thought it would make a nice setting and contrast to their ceremony. I always hate fics that demonise the exes of either of them, so I've tried to steer away (bar for one obvious joke). Anyway, I love feedback, so please leave a note with your thoughts. Thank you.