A/N: This fic is a collaboration between Bec/AnnieXM and Lou/lousiemcdoogle. It's pretty much completely written, aside from a wee bit of editing, and should be about five chapters long and updated daily. If you have any questions about how we came to decide dates, feel free to PM either of us and we'll happily answer your questions.

*RATED T FOR NOW, BUT THE RATING WILL CHANGE TO M IN LATER CHAPTERS*

Bec's note: Thank you, Lou, it's been a blast tackling this prompt with you. Let's do it again soon!

Lou's note: It has been SO MUCH FUN co-writing this! Thank you, Bec, for making my words sound good :-)

Disclaimer: Castle belongs to ABC and AWM.

Prologue – Present Day

"T-minus 72 hours until we are married. This feels like a dream," she cooed, grinning at him like the lovestruck fool that, even a couple of years ago, she would never have thought she would turn into. This was it, the moment the marriage certificate would be obtained and the last obstacle between them and their big day removed.

He matched her grin, his eyes sparkling with joy as he leaned in closer to her. "That's because I'm dreamy."

His voice was pitched deep and the low timbre sent a delicious shiver up her spine. The giggle bubbled out of her, and she gave him a playful nudge to his side with her elbow. "Oh, shush," she mumbled, a soft blush coloring her cheeks.

Anything he might have said next was interrupted by the clerk's abrupt, "Next!"

"Oh." He sounded disappointed their moment had been interrupted, but this was, after all, why they were here. She watched as he handed over all of their paperwork. "Here you are."

The clerk couldn't have sounded less interested as she ran her eyes over the forms before her and said, "Mr. Richard Castle and Miss Katherine Beckett."

"That's us." He gestured between them, and she couldn't help but loop her hand through his arm. She rested her head on his shoulder, and allowed a happy smile to play on her lips. For once everything was falling into place.

"Proof of divorce?" the clerk asked.

Castle handed over the necessary papers, and the clerk checked through them briefly, before putting them aside and staring at the pair of them expectantly once more.

"Is – is there something wrong with my documents?" Castle's voice squeaked in the adorable way it did whenever he thought he was in trouble. She'd have to think of some way to make him squeak tonight after...

The clerk's abrupt voice stopped that train of thought. "I'll need the rest. Also, Miss Beckett, do you have yours?" she asked.

Kate's head shot up. "Pardon me?"

"The rest?" Castle echoed. "Wait, yours?"

"Your divorce paperwork." the clerk repeated to Beckett.

Kate chuckled in disbelief, but there was a nervous edge to it – something in the back of her mind telling her the clerk was right. "I'm sorry, there's a mistake. I've never been married."

The clerk was not to be put off. "Well according to this, you have. And it looks like you still are," she said, indicating to her screen.

"I'm married?" Kate repeated. "To whom?" She was trying to get a look at the screen for herself, to see it with her own eyes. Married? No, that wasn't right. She would know if she was married. But the niggle, the strange sensation in her mind, remained unwavering.

The clerk took a closer look herself, finally taking an interest now that it appeared there was an issue. "That's odd," she began, lifting her eyes to take in the bewildered couple before her. "It says here you're both already married... to each other."