For ages, me and defiant_chic have been spending inordinate amounts of time talking about all the songs that are "so so Casketty". So, I got bored at work, and started writing the first few lines of dialogue and then this got out of control. Then defiant_chic told me she wanted more, and kimmiesjoy told me I gave her feels and convinced me that this was worth sharing. So, a massive thank you to both of you for re-assuring me I'm not just a raving lunatic.

This is set somewhere in season 6, as long as we're pre-wedding (because, you guys, there's going to be a wedding!) and post-DC you're all good.

Disclaimer: I think the comment above really highlights that I don't own Castle. If I did, I would never be bored at work.

"Kate… Whatcha doin'?"

"Going through your iPod," the detective replied, as she continued swiping her thumb across the screen.

"Why?"

"Because you sleep like the dead. And I wasn't ready to get out of bed yet."

"And you didn't feel like reading one of your partner's books?" Castle replied, looking pointedly at the latest Nikki Heat on her bedside table, "I hear he's pretty good."

"Oh, he's very good," she replied with a salacious grin, "but, nope," she finished, popping the 'p'.

"So, my question still stands; whatcha doin? There's nothing exciting on my iPod, all my games are on my phone."

"I've already beaten your high scores, Castle. Besides, you'd be surprised at what you can learn about someone from their choice in- You have a playlist on here called "All the songs make sense"?!"

"Uh… yeah. I mean- Is that still on there?" The writer suddenly looked sheepish, and Kate would have called the look in his eyes somewhere between embarrassment and fear.

Narrowing her eyes suspiciously at Castle, "Yep, it is," Kate returned to the device to thumb into the playlist, "Why are you looking at me like that?"

"Just… Nothing, no reason. You want breakfast?" Gesturing towards the bedroom door, his weak attempt at changing the subject not lost on the detective, "Now that I'm awake I'm sure you're bored of scrolling through my iPod," he started to makes moves as though to get out of bed.

"Nah, I'm good. Is this playlist about me, in some way?"

"Wh- Why do you ask that?" Castle all but spluttered, tried to disguise it with mild curiosity.

"Because this was something I said to you, once upon a time."

"You remember that, huh?" Castle ran a hand through his deliciously sleep mussed hair; resigned, if Kate didn't know any better.

"It was something my Mom had said to me, so yeah, I remember," she replied, smiling at the memory.

Castle propped his head up with his left elbow on a pillow, expression morphed into intent interest as he wordlessly encouraged Kate to elaborate.

Sharing. Right. They did this now. Come on, Kate, you can do this. And she could. She'd been doing it ever since Castle had bribed his way into her life, though in the past year or so it had been more deliberately, less unwittingly.

"I was with my second real boyfriend, Aaron, my freshman year of college," Kate began, smiling in remembrance, "I'd never felt like I did with my first boyfriend and I thought it might have been love. And so on my next trip home I asked my Mom how I'd know if I was in love, and she said, 'Well, Katie, I knew I was in love with your Dad when I was listening to love songs and all I could think about was him.'" Kate glanced up at Castle from where she'd been staring at her hands, the look in his eyes giving her the strength to continue, "I went back to my dorm room and started to listen to the radio, trying to pay attention to the love songs and figure out if the lyrics matched how I felt towards Aaron."

Rick smiled at the imagery of a nineteen year old Kate Beckett, sitting on the floor listening intently to the radio to prove if she was in love with a boy.

"And were you?"

"I think I thought I was? Nineteen year old me had no idea what love is, what being in love feels like, not like this," she gestured between the two of them, eliciting grins from both of them, "I think I wanted to be in love, and so I made the songs make sense for Aaron. It wasn't what my Mom was talking about though. That was in December, over the Christmas break before…" she didn't need to finish the thought, and took a breath before continuing, "It was the last piece of 'life advice' she ever gave me, it's not something I throw around all the time."

"But when I asked you, we weren't even… anything. Why would you tell me?"

"You were wearing that stupid steampunk outfit! I was so caught off guard, I just didn't even have time to filter myself," she explained, "And Castle?"

Castle hummed in acknowledgement as Kate leaned down to gently card one hand through the soft hair at his temple.

"We were always something, it just took us too long to admit it."

Anything he might have said had was quickly swallowed by her mouth as she leaned the rest of the way, her lips meeting his in a gentle kiss. Castle responded with a little more insistence, tongue sweeping out to touch her bottom lip to the rhythm of her light moan.

It was Castle trying to gently take the iPod from her grasp that brought Kate back to why they'd just had that conversation.

"Hey!" she exclaimed softly, breaking from his welcome intrusion, putting a few inches between them with her other hand on his chest, "I showed you mine, so you have to show me yours," at his raised eyebrow and pointed glance down to where she was at least covered by an oversized t-shirt once belonging to Castle, "Not what I meant, dirty! I told you my story, so your turn: why do you have a playlist called 'All the songs make sense'?" She wiggled down, mirroring Castle's pose propped on her right elbow.

"You know how you said it just took us too long to admit we were something?"

"It was like, two minutes ago, Castle," Kate replied, jokingly rolling her eyes.

He poked his tongue out playfully before continuing, "Well, I think this was my way of admitting that we were something, at least to myself, before we were… something." He waggled his eyebrows, "At first, your words meant nothing—well not nothing, obviously, because everything you say means something to me," he babbled, "But I really had only asked because of something Alexis had asked. But then I started to think about them, and I started hearing songs and realised I was thinking about you."

"That's…" Kate began, looking down to the iPod, resting between the mattress and her hand.

"Lame? Weird? Sappy?"

"I was going to say sweet," she smiled warmly, "but sappy and weird work too."

"And then I just had all these lyrics floating around in my mind with no real direction. I'd hear a song in a store and have it running through my mind for the rest of the day. So, you know how to only way to get a song out of your head is to listen to it? Well, I'd have to go home and download the song, and then the playlist just kind of grew on its own; every time I'd hear a song that reminded me of you, I'd add it to the playlist, and well… here we are," he took a breath, "Turns out you're not as easy to get out of my head."

Kate released the iPod, grasping Castle's free hand with her left, "Never getting me out now," her soft words enunciated by the cool metal band around her left ring finger, pressing into the space between his fingers.

"I'm stuck with you, huh?" he bantered back.

"Always."

"Isn't that usually my line?"

She poked her tongue out, trust Castle to lighten the moment, "Well, but what's yours is mine, right?"

"Not yet, not until you're officially Mrs Katherine Cast—oww! I take it back! What's mine is yours now! Forever! Whatever you want!" he quickly amended, gently rubbing his ear when she'd tweaked it.

"And do you know what I really, really want?" her voice dropped, looking up at him through long lashes as he leaned forward eagerly.

"Mmm?" he licked his lips.

"To know what songs reminded you of me, of… us," she admitted softly, the words ending up more sincerely, less teasingly, than she'd intended.

"There's a lot of songs on there, might take us a while to go through them," he warned.

"It's a good thing we have the rest of our lives, then," She caught and held his gaze, catching forever in his eyes.

Thoughts? (good, bad or otherwise, I'd love to hear 'em!)