Hi all, just a sweet, slightly salty, very nutty little one-shot.

DISCLAIMER: Did you see the tweet from Terri Edda Miller a couple of days ago, which consisted of nothing but "hehehehehehehe". Now, would I be that cruel? Of course not. Henceforth, I don't own Castle.

...

Castle glanced up from his laptop at the sound of Kate groaning. She was sitting on the couch in his study, her hand pressed tight against her abdomen, evidently in anguish.

"Kate, you OK?" His concerned voice asked her.

She waved a hand dismissively in the air. "Yeah, yeah, just a little cramp."

"Oh, that time of the month, huh?" He asked, saving his document and closing the lid of the laptop.

"Uh...yeah, I guess it is."

"Mm, anything I can do to help? Back rub?" He asked, already standing and walking over to her. In the low light of the room, his height and astute posture made him appear quite the knight in shining armor.

Kate gazed up into her fiance's dazzlingly blue eyes and grinned. "Oh, Castle, that would be amazing."

He smiled back softly and went to sit down on the couch next to her, until her voice halted him. "Would you mind getting some oil?"

Ever the dutiful partner (Well, okay, not usually, but sometimes he actually proved to be diligently responsive), Castle offered her a smile again and headed for the ensuite to retrieve the massage oil he'd purchased during their recent trip to Bora Bora.

He'd bought two bottles, as the first one had been nearly totally emptied during their romantic vacation, where they'd spent a fair bit more time inside their hut than out of it.

"Oh no, Castle, can you get the peanut oil from the pantry?"

"Peanut oil?" Castle frowned at her odd request. "As in the stuff we used tonight in the lamb tikka masala?"

"I've read it's really hydrating and good for the skin", Kate explained, throwing him a look that was half "I know what I'm talking about, don't argue with me", and half "Please be a dear, I love you."

Castle inhaled a long, deep breath, shaking his head, finally conceding. "Alright, peanut oil it is." He nearly made it to the door before his inner smart-ass managed to find its way out.

"You want fries with that?"

...

The next morning, while at the precinct, the case had officially been closed as Beckett dotted the final 'i' on her report.

She looked up from the page, rubbing her eyes wearily. She stretched her arms above her head, leaning back and letting her vertebrae readjust itself. "Thank God that's done, oh man, and suddenly I'm starving. Castle, could you get me my secret stash of trail mix from the break room cupboard, please?"

Castle took a sip of freshly brewed java from his coffee cup, his face a picture of grace and obedience, despite having only been in the break room three minutes earlier to make the coffee for the both of them.

"For you, Detective? Anything."

She gave him a grateful smile and he rose from his chair, whistling cheerily on his 30 meter journey to the break room.

He headed straight for the lower left hand cupboard, glancing around with a narrowed-eyed suspicion, should anyone be watching. Far be it for him to reveal the location of Beckett's secret stash of snack food, to any nosy passers-by.

He opened the cupboard door quickly and covertly, retrieving the packet of trail mix. He paused for a moment before slowly closing the cupboard door. He studied the packet with intense concentration, as if working on a complicated puzzle. And indeed, he was; puzzled.

He made the short walk back to his partner's desk and bit his lip nervously, unaware what her reaction might be when she found out.

"Uh, Beckett? There's nothing but nuts in this bag of trail mix."

Kate stared at the bag that he held out in front of himself, the same confusion on her face as on his. "What happened to the fruit a-and the carob? Where's my carob, Castle?!"

"I-I don't know, I swear!" Castle grimaced, already sorry he hadn't just snuck out the back of the precinct and run down to the store to get a new batch of trail mix.

He knew how moody Beckett could get when she didn't have her snacks.

She sat back in her chair, leveling him with her look. She slapped her hand down on the closed case file. "Well Castle, I guess we just got landed a fresh case."

His eyes shifted left to right. "Huh?"

Beckett nodded stiffly. "The mystery of the lone nuts."

Castle raised an eyebrow, his face turning red with the effort of refraining from making a sexual joke.

...

That evening after they had unsuccessfully managed to crack the case of the missing trail mix components, or "crack the shell" of the "nut case", as Castle had put it, the two of them went home and decided to simply veg out on the couch. Castle was reading the latest work from one of his competitors when Kate nudged his arm with her shoulder. "Oh man, this is right up your alley, Castle you have to watch this."

He frowned as he glanced up from prose that was far too gaudy for his taste. "What is it?" He asked Kate.

"It's a short film directed by Robin Williams."

He grinned at her. "Now that guy is a comedic icon. What's the film called?"

Kate turned the screen of her tablet so that he could see.

"Walter ate a peanut", he read aloud, his brow creasing.

"Mhm, it's really weird, but it's your kind of weird", Kate assured him, and together they watched the 6 minute black and white sardonic short.

When it was over, and Kate was looking at him expectantly, Castle had to force a laugh.

Weird was right, and not even remotely funny.

And he had kind of just lost a little bit of respect for Robin Williams.

Clearly Kate didn't know him as well as she thought she did.

...

The next day, Kate had a miraculous mid-week day off, on which she managed to convince Castle to take her to the zoo.

"Come on Castle, I wanna see the elephants. You know how I love the elephants!"

He did know how she loved the elephants. The way they moved their huge limbs so delicately and slowly. She found it majestic, and soothing. When her world was filled with such deliberate harshness, done by those who were much less capable, the elephant, in all its enormous power, was graceful and gentle.

So, off to The Bronx zoo they had ventured, meeting with, and feeding a 43-year-old female Asian Elephant named Patti.

Castle watched Kate, watching Patti, along with her two companions, Happy and Maxine, as they silently negotiated their enclosure. The wonderment in her eyes as she observed them, had filled him with a surge of devotion.

They returned several hours later to the parking lot where their car was parked, and Castle climbed in the drivers seat (he had only been allowed to drive because of the phrasing she herself had used. "Castle, can you take me to the zoo?") Therefor, he argued, he was allowed - nay - obligated to drive.

When Castle, wearing a wide and satisfied smile sat down behind the wheel, he felt an uncomfortable cracking beneath his posterior. He made a face, reaching into his back pocket. "What the-"

"Castle, why didn't you take those out of your pocket? The material will be stained with oil and shells."

Castle realized, with dread that he had sat on top of a packet of peanuts that had not quite been emptied when they had used them to feed the elephants.

"Why were they in my pocket in the first place?!"

"I told you I was putting them in there", Kate defended herself. "My bag was full because you insisted on buying that stuffed black bear!"

"Hey, you leave Jacques Aubert out of this", he retorted, wining as he pulled his pocket inside out and grumbled about the cleaning bill that would be incurred.

As he revved the engine of his car, he couldn't help feeling like some kind of conscious, recurring nightmare was being played out here. Like a horror film, with the reel jammed in the projector, flickering relentlessly in an never-ending loop.

Or maybe he was just being dramatic.

...

Later that night, the two of them were once again sprawled out on the couch, after finishing eating the delicious satay chicken dish which Kate had cooked (Castle was almost ready to make mention of the weird recurrences of the now alarmingly ever-present snack food, when he tasted his fiance's cooking, and immediately plowed into it, soon falling into a delicious food coma, and forgetting the whole thing.)

Until...

"Castle, I need you to go to the market for me."

"Kaaaate, I'm too full to even think about moving from this chair", Castle could barely bring himself to crack an eye open.

"Please Castle, I really need you to pick up some peanut butter."

And there it was.

Somehow, he'd been expecting it, he'd tried ignoring it, demanding himself to accept it as a simply coincidental little quirk. But now that it had been mentioned again, it had finally driven him, metaphorically, and literally, nuts.

"Alright!" He yelled, jumping up from his chair, feeling slightly maniacal even as he did so, though unable to stop it. "What is with the damn peanuts?!"

Kate gaped at him, making him feel like he'd truly lost the plot. "What are you talking about?" She asked him slowly.

"The nuts. The nuts, Beckett! First it was the uh - oh yeah, the peanut oil, you wanted me to rub on you? I mean what are you Kate, a baked potato?! Then it was the bag of trail mix which was void of everything BUT nuts. Then it was the film, which, I'm sorry, was so tasteless, even I, the purveyor of bad form, was left cringing! Then today with the zoo and the elephants and the peanuts in the pocket of the pants, and the whole thing just feels like I'm literally going into anaphylactic shock, like I'm being choked to death by the image of these salty little demon snacks, so much so that I now feel like I'm one of them!" He finished his passionate rant, red in the face and panting.

"One of whom?" Kate asked him, her face a picture of one freaked out.

"The nuts!"

Kate stuttered. "Ah-um. Are you personifying nuts?"

Castle nearly blew a fuse. "I-" He puffed out his cheeks. The steam almost visibly coming out of his ears. "Look Kate, I don't know what on earth is going on here, but I am tired of trying to keep up. I'm going to bed."

"But what about my-"

"Get your own damn peanut butter. I don't want to hear anything about it!"

"Well that's great, Rick, I get my first cravings and you won't even run down and get the ingredients for me to make a peanut butter and pepperoni sandwich."

Castle shook his head, gagging. "Who the hell can even digest that kind of food combination unless they're-"

Oh.

"Cravings?" He swallowed thickly. Silently, and insanely wondering for a moment, if he was indeed experiencing anaphylaxis, due to the lump that had suddenly formed in his throat.

Castle's eyes traveled up and down her body, flickering between her glowing smile and her not yet protruding belly.

"Kate, are you-?"

She was biting her lip, not bothering to tamper down the beaming smile that had overtaken her face.

Castle breathed a note of awe, his tone so much softer now it was barely audible over the sound of his own racing heart. "We're having a- a...peanut?" He asked, his eyes wide in childlike wonderment, already pooling at the prospect of what lay ahead.

Kate laughed lightly, immensely glad that he'd finally caught on. (Truth be told, she'd been running out of peanut-related ideas to confuse him with.)

He had been wrong last night. Kate knew him very well indeed.

She knew him so well that she had spent the last few days carefully concocting and executing pranks surrounding "peanuts", to create a mystery that would slowly draw him to just the tip of the crazy iceberg before throwing him head first into the intensely cool revelation that she was pregnant with their son or daughter.

He grabbed her (carefully, of course), by the hips and pulled her small body into his own. He held her mightily. This woman, this wonderful woman of his. Love of his life, and now the vessel carrying his unborn child.

"How far along are you?"

"About 6 weeks."

He gasped excitedly. "That means we should be able to have our first scan soon."

"I know, I booked an appointment for Monday. I was going to wait and just drag you along to the clinic, surprising you when we got there, but this was way more fun."

Castle chuckled into her hair. "I remember Alexis's six week scan, I was so confused when I didn't see a baby, but some kind of blob, shaped kind of like a...", He laughed loudly, hugging her tighter.

"Oh Kate, Kate, Kate. I love you so much. So much", he whispered into her ear.

"I love you too, Rick."

He felt her hands on his arms, pushing her away from him. He looked at her in alarm. "What is it, am I hurting you? Am I hurting the baby?"

Kate stopped his panicked ramblings by placed a calming hand on his face. "No, no of course not. It's just that, well...I was serious about the peanut butter and pepperoni sandwich."

...

A/N: So, I'm not sure if this was more cheesy than it was weird, or vice-versa. Also, I actually have a little stuffed black bear called "Jacques Aubert." I thought I was so clever when I dubbed him with that name, and then taught my 3 year old niece to say it.

P.S. Would love a review. Please? :)