Disclaimer: Not mine, never will be. (Except when I experience bouts of delusion.)

Summary: Speculation Fic for 5x06. Spoiler-based, so beware! A final scene for The Final Frontier.

Notes: Wrote this last night after watching the Sneaks. Wasn't going to post it—I really just needed to get the idea down so it would leave me alone—but then figured why the hell not? So… here it is: a Final Frontier Ficlet for your reading pleasure! Enjoy!


"So, K-Becks…" Castle taunted from the kitchen, hoping she could hear the smirk in his voice, "is there a reason you've been keeping your inner geek a secret?"

They'd arrived at her place just after seven, having come directly from the Convention. Beckett had (for the first time in history, Castle was certain) agreed that the paperwork on the Anabelle Collins murder could wait. She'd made a beeline for the bedroom the minute they'd walked in the door while he poked around for something to eat.

"You call me that again, Castle, I'm staying in here by myself," she said, appearing in the doorway to lean seductively against the frame. "And I don't think you want that."

Castle closed the fridge and started toward the bedroom but, catching sight of her, suddenly rooted to the spot. There stood Beckett, in all her Nebula 9 fangirl glory. The uniform was tight, the skirt was short, the heels were sky-high. She was… extraordinary.

After two attempts to swallow past a grapefruit-sized lump in his throat, Castle finally mustered a hoarse plea. "Do I get to boldly go where no man has gone before?"

"That's Star Trek's tagline, Castle," Kate chided, shaking her head. "Besides, I think you've already accomplished that particular mission."

At his befuddled expression, she came to him and brought his hand to her chest, pressing it lightly over her heart, smiling shyly.

Castle melted.

He leaned in to kiss her, slow and sweet, even as his own heart caused his pulse to rocket.

"It's not a secret, you know," she murmured when their kiss became little more than the lightest meeting of lips.

"Hmm?" His hands had begun to roam. The material of the uniform was softer than it looked. And, well, her amazing body was there, just under it, warm and responsive and….

"No secret," Beckett repeated, stifling her amusement and squeezing the nape of his neck to catch his attention.

When she had it, or as much of it as she could reasonably expect, she continued. "I was lonely my first semester of college. Homesick, didn't know anyone… it was hard. I came across the show one evening when everyone else was out partying. I identified with Chloe. She was bad-ass and brave—even so far from home—and totally determined to make her mark. I wanted to be that, too. She gave me a template, I guess. It got me through that first semester."

"That's not so bad," Castle said with a smile. "If that's all, though, if it's not a secret, why did you confiscate that photograph from poor, unsuspecting Harry?"

"Having a fictional role model isn't so bad," Beckett agreed. "But dressing up like her, essentially playing pretend? That part may be a little embarrassing."

Castle scoffed incredulously. "You were embarrassed because you indulged in a little escapism? Beckett… it's me. And also, you do remember that it's my job—my honor, really—to provide a similar means of escape to the masses?"

"Yeah, I know," Kate said. Something in her tone piqued Castle's interest, but she waved him off. "So you don't think I was a little extreme?"

"No. Extreme would be if you'd written love letters to Captain Max and… ohmigod, Beckett, please tell me you didn't—"

She socked him in the arm, hard enough to staunch the flow of speculation.

"No. No love letters. Although, now that I've seen him up close and personal…" Beckett teased.

"Oh no you don't," Castle warned, dragging her roughly against him, making her gasp. "This is mine."

His thumb brushed in a wide sweep just under her left breast as he claimed her mouth in a deep, deliberate kiss that sent her flying.

When Castle's lips left hers some minutes later, traveling lazily to the underside of her jaw, she was in the stars.

"So what's the tag for Nebula 9, then?" he murmured, one hand skimming up under her skirt to trace the contour of her hip.

Beckett struggled to grasp the question. "What? Oh. It's… um… 'Solving the universe, one mystery at a time.'" Her voice wasn't exactly steady, but she was in too much of a haze to care.

Castle pulled back, a delighted grin on his face.

"I like it. Should we start with what in the world is in that red Tupperware container at the back of your fridge, or might we move on to more… enticing enigmas?"

"Your call," said Beckett, summoning all her reserves to push away from him and saunter toward the bedroom. He was still a bit too coherent for her liking. But she knew how to fix that.

"Though, if it's a real challenge you want, there's one specific mystery I'd love you to help me solve."

"At your service, Lieutenant," Castle submitted as he followed Kate Beckett, Nebula 9 Officer, out of the kitchen, all thoughts of food long since forgotten.

Beckett climbed onto the bed, knelt there and motioned for him to come stand in front of her.

"I haven't worn this costume since I was 18," she admitted, giggling as she ran her hands up his chest, over his shoulders, into his hair.

"I got into it, somehow, but I'm not quite sure how I'm going to get out of it."

Castle smirked and slid his hands up her bare thighs, in love with the way her eyes darkened at his touch. "Fortune must be guiding your journey, Beckett. Getting you out of your clothes has, happily, become a specialty of mine."

"Happily," she echoed.

And as he put his recently-acquired skills to good use, she couldn't help but think, Solving the universe, indeed.