A/N: I've been watching reruns of Castle lately and I have about a million and one ideas bouncing around at the moment. Of all of them, this one really stuck. Also, this happens to be my 50th story! Yay! Please enjoy this. :) Reviews are always loved.

I don't own Castle.

"God, Castle, it's been a long day."

She let out a tired sigh at the end, a lazy half-smile on her face as she stared at him. They were seated beside one another on her desk, facing each other as though no other person existed in the world. Of course, they were hardly alone; it may've been eleven o'clock at night, but there was always another cop working, no matter the time. Really, the pair should have been at home, considering they'd just wrapped up a case and were utterly exhausted, but, being without plans, they hadn't moved for just over an hour.

"Yeah, it really has," he agreed, nodding slowly. His words were punctuated by a yawn, which she quickly matched after a failed attempt to push down the urge. "I can't believe I haven't slept in twenty-eight hours!"

"Neither can I. This has been insane. Next time we go chasing leads, we should probably make sure we either have coffee or sleep beforehand."

"Mmm," he hummed in agreement. "Or how 'bout we just get a GPS? I'll start looking for one tonight." After a yawn, he quickly rephrased, "I mean, tomorrow."

"Hey, we wouldn't have gotten lost if you hadn't said 'turn right' when we were supposed to turn left."

"Oh, so it's my fault now?" his tone was teasing, but tired. She shrugged at him. Of course it was his fault; he really had given her the wrong directions (just when she'd trusted him with a map), and they'd ended up in a whole other state before realizing their mistake. It had given the suspect enough time to get into the wind, but they'd hit a lucky break - the man had crossed the state line just as they had.

"Of course it's your fault," she shot back, but her expression turned quickly from teasing to serious. "Still… you redeemed yourself pretty well."

Castle's face sobered just as rapidly. "Yeah, I guess."

She forced herself to smile at him. They sat, staring at one another, for several minutes until the sound of footsteps startled the pair. Curious, Kate looked around, but, finding nothing, returned to Castle's gaze. "Thanks, Rick. And I mean that."

"Always," he whispered softly.

A rather loud crash startled them both once again, and they turned; the cause of the noise was not hard to spot. Just a few steps away, Josh stood, looking both irritated and confused simultaneously. Realizing their current situation, Castle stood up off the desk, backing away from Kate. He gave her a small smile and mouthed "goodbye," before stumbling away, cursing Josh.

That man had such bad timing.

"Always?" Josh asked sceptically, taking a step towards Kate. "What's that supposed to mean?"

"Oh, it's just a writer thing," Kate tried to explain, shrugging in attempt to throw him off the subject. "So… what's up, Josh? Why're you here so late?"

"I got some time off. You weren't at home," he answered shortly. "But seriously, why are you here so late… with him? Why's he saying 'Always?' What does that mean to you?"

"Don't get worked up. It's nothing."

"Kate, we were supposed to go to dinner tonight, remember? So I'm sorry if I'm a bit irritated to catch you staring into writer boy's eyes like he's the most important thing in the world."

Beckett gritted her teeth in frustration. She should've seen this argument coming; as much as Castle detested Josh, it was nothing compared to the doctor's thoughts of him. She'd thought that, the last time they'd gone through this, the fights would stop, but obviously Josh had no intention of letting it go (of course, the voice in the back of her mind whispered, wouldn't you feel the same way in his position?).

"Josh, I'm sorry we didn't get to go to dinner. We got caught up in a case and I figured you'd understand."

"Yeah, fine, I get that, but I still don't understand why you were here with him instead of at home."

"I was tired. We both were. We figured we'd stay and chat for a while."

"Okay, but 'chatting' doesn't constitute the look you had, or whatever the hell 'always' means."

"Get a dictionary. I'm too tired to deal with this." Irritated, she rose and started to walk away, but his hand shot out and gripped her arm. A glare blossomed on her face and she spun on her heel to face him. "I'm done with this, okay? Castle's my partner. And 'always' is… nothing."

Even before she spoke the last word, she knew it was a lie; always was more than just nothing, wasn't it? It signalled just how deep their bond ran, and it told stories of the heart, stories they'd never speak aloud. It hurt to pass it off as nothing, but she could hardly look at him and say, "Castle and I say 'always' because it shows how much we mean to one another. It means he's always going to be here for me, and I'm always going to be there for him. If you don't like it, then you can leave, because always is forever."

"It's not nothing," he sighed. "Kate, why are you lying to me?"

"Because you can't handle the truth. Hell, I can't handle the truth."

"Are you cheating on me?"

"God no, Josh, I-"

"Then why can't you tell me what a damned word means?"

"Fine," she huffed. "'Always' is… I don't know how to explain it. It's not nothing, it's everything. Everything about him, about me, about our lives and the job. It's everything in this world, everything between us, in one simple word."

'Well,' she couldn't help but think, 'Castle would be proud of that. I sounded… writerish. Eloquent. I hope.'

"Why does it only pertain to him?" Obviously, the explanation wasn't causing Josh to back off; he was only getting more irritated, a glare of pure rage dashed across his face. Maybe honesty wasn't always the best policy - at least not in cases where Castle was involved. "Why couldn't I say 'always' to you?"

"Because you're not Castle," she muttered. When he frowned, she repeated, louder, "You're not Castle, Josh. You and I are different than… than me and Castle, okay? If you said 'always,' it wouldn't mean anything but what the dictionary says. When he says it…"

Josh suddenly let go of her arm, spinning away from her and stalking off towards the elevator. After a few steps, he stopped, turned back, and growled, "It's not everything. That's not what it means at all, is it? That's your way of saying 'I love you.' I should've known you were head-over-heels for the guy, I should've-"

"Josh, what the hell are you saying?"

"I'm saying we're over. Because if the only person you see always with is him, then you're not worth my time. You're not worth anyone's time."

"But-"

"But nothing, Kate. Goodbye."

Growling in frustration, the detective threw herself into her chair. She briefly contemplated chasing after him, but that wouldn't accomplish anything - because he was right, wasn't he? Maybe it didn't mean 'I love you,' but she couldn't see a future - an always - with Josh.

But she could with Castle.

Sighing, she grabbed for her phone and quickly texted an 'I'm sorry' to both Castle and Josh, knowing that the former was likely asleep and the latter would probably have her number blocked by now. She laid the phone back on the desk and stared at the blank murder board, allowing her thoughts to take her away. Unfortunately, she wasn't given much time for this as her phone buzzed beside her. She grabbed for it, a small smile gracing her features at the words and the sender (Castle, of course; she should've guessed he'd text back this late): 'Hey, no problem.'

A second later, another text arrived. 'Wait, you're still awake? Are you still at the precinct?'

'Yes, and yes, why?' she responded as fast as her thumbs would let her.

'Come by for some ice cream and a movie? :)'

'I don't know…'

'Oh, come on! It'll be fun.'

'Alright, fine. I'll be there soonish.'

'YES! :D!'

'Lol. :) Thanks again… for everything. I'm glad you were there.'

'Hey, no problem. I'll always be.'

'Uh-oh, am I stuck with you? :p'

'Yup. Always.'