A/N: So um, this was supposed to be up at Halloween but my laptop crashed for a couple of days. :( But since it isn't very Halloween-y anyway I thought I'd still post it. A huge thank you to my betas kimmiesjoy and Indie but especially to Kimmie who made me this hilarious cover art 2 weeks ago when I first told her about my idea. And I wanna add that she made it before Myko Olivier posted the pic of his "Pi pumpkin" on twitter (I may have squealed a little ;)).

Disclaimer: I own nothing.

He used to love pies; in all shapes and forms.

His favorite as a kid had always been pumpkin pie. He'd go out of his way to get a piece at least once a week. Throughout his life, for no particular reason, he'd always favored that kind of pie, so when his daughter was born with that bright red hair his moniker for her came naturally.

Pumpkin. His little pumpkin.

His love for pumpkin pie remained, even if over the course of the years other kinds of pies made their way onto his table…and into his heart.

Over the last five years he'd developed a certain fondness for cherries. Gradually, they became one of his go-to dessert choices, besides all kinds of pumpkin things of course.

His taste usually depended on his mood. If he was looking for something familiar and homey he'd go to the store and buy pumpkin pie. Or make it himself from scratch.

If he was feeling a little more adventurous and daring, longing for something sweet but also fruity and equally luscious he'd go and get himself something cherry flavored.

Pumpkin and cherries – his two most preferred and beloved fruits.

But this year when Halloween was right around the corner, and he and Kate were planning their first real pumpkin carving as a couple together, he suddenly didn't feel the usual excitement that came with that time of year.

Alexis had excused herself from the annual Casa Castle pumpkin-carving-contest since she and Pi wanted to do their own carving in their new apartment. So naturally his mood was a bit sour during the days leading up to Halloween. When he came home the night before, laden with two huge pumpkins, the air was filled with the delicious smell of baking goods.

He entered the kitchen to find Kate finishing up the last touches to what looked like…was that –

"Hey, you're home. I'm making pumpkin pie! Your favorite."

Interrupting his train of thought she sidled up to him, cheeks flushed from the heat in the kitchen and a huge smile on her face, pressing a sweet kiss against his lips, love and a little excitement practically leaking out of her.

He knew she wanted to cheer him up but he suddenly couldn't help but flinch.

Of late his distaste for pi(e)s in all shapes and forms - especially in the mathematical but also (somewhat) human form - was already quite big, but the connotation of Pumpkin Pie of all things was even worse.

Just thinking about mashing pumpkin together to make Pie gave him the heebie-jeebies. Images formed in the back of his mind and - yeah! No! - maybe think about cherry pie instead…

Ugh!

His thoughts came to a screeching halt and he did a double take.

Hell no!

Cherry Pie was out. of. the. question!

Nope. Nope. Nope.

Shuddering, he actually pressed his knuckles into his eye sockets trying to dispel the thoughts and images in his mind, to squeeze them out like the foul, disturbing…fruits of his imagination they were.

Ugh! No more Pi!

"Hey, everything ok, Castle?"

"Yeah. Yeah…it's just…god, I'm sorry but I've kinda had enough of Pi lately to last me a lifetime, thank you very much!"

Her confusion turned into amusement. "Come on Castle, don't be a drama queen. It's just pie."

"Yeah, exactly. It's Pi." The disgust in his voice couldn't be more evident and he shuddered again just thinking about it.

"So what you really want to tell me you're saying no to a big piece of…," she paused for effect and licked her lip for good measure. "…delicious, hot pie?"

He whimpered, the onslaught of images just wouldn't stop. To his horror Kate kept going, slowly, deliberately closing the distance between them again, her voice dropping to a low seductive tone.

"Think about it, Castle. Hot pie covered in cool whipped cream, melting all over the top…," she trailed off suggestively, her hands roaming his chest, dipping ever lower.

He recoiled as if burned, the urge to gag suddenly rising in his throat.

Turning eyes as huge as saucers and full of terror to Kate, he was met with…her pursed lips? There was a twitch playing around her mouth she was unable to contain.

Really?

"Are you…you're…you're messing with me?" His voice rose to an incredulous squeak at the end, barely able to wrap his mind around the fact that she had just played him.

Kate laughed out loud, not able to contain her mirth any longer at his overly dramatic and horrified expression, "Come on, Castle! It was just too good to pass up."

When she gazed at him, his face must have still looked like he'd just bitten into a lemon because she doubled over again, shaking with laughter and swiping at her eyes.

A little dumbfounded, he realized he really was being a bit ridiculous and couldn't contain his own chuckle now. Grabbing her suddenly, he spun her around, up against the counter, pressing a hard and hot kiss against her mouth, swallowing her squeak of surprise.

"Oh you little minx, you will pay for this. Dearly."

"Promise?" She whispered breathlessly, so he swooped in again, letting his tongue swipe against her own, taking her mouth in a series of hot, wet and dirty little kisses.

Before they could get too carried away though she pulled back and ducked out of his reach. Panting and flushed from their ministrations she smirked at him, "But first, let's finish up here, after all the pie is still waiting to be done."

And just like that the lust clouding his eyes dissipated a little and he winced. Audibly.

Laughing, Kate snaked her arms around him again and nuzzled her face against his neck, trailing little kisses along his jaw, whispering into his ear. "Hey, no thinking about Pi tonight, ok? The human Pi, I mean. If you help me finish up here, I promise to make it worth your while." She peered up at him under her lashes, throwing him a dark and promising look.

"Pi? Who's Pi?"

Her throaty chuckle made him wonder why they even bothered with dinner, his current hunger was of a very different nature entirely.

"Ok, focus Castle! What does the recipe say about cooking time?"

"Uh…right. Let me see. It says here around 40 minutes at about 400°F." He couldn't help sweeping his eyes across the page, taking in the pictures of half-made pumpkin pies and again he was reminded of the latest developments in his family.

Ugh. No.

Trying not to let his mind go there, he was about to close the book when his eyes caught a line of the descriptions in the recipe.

You can even freeze the pie after cooking it.

Oh.

Well.

Maybe this whole Pi thing wasn't so bad after all. The instructions here at least seemed to be quite useful.

A lot more interested now, he decided to take a closer look and rapidly let his gaze skim the page.

Mash the pie.

Cut and roll it out.

Hmhmm, very promising.

Squish it well in every corner of the pan.

He bobbed his head in agreement.

Bake the pie at 400°F.

Yesss!

It's possible to freeze the pie.

Oh yeah, his eyes took on a dreamy, slightly mad glimmer and he let his imagination what else he could do to Pi run wild.

Suddenly in a much better mood he went to help set the table, his mouth quirked up in a little devious grin.

"Uh…Castle, what…what are you doing?"

Dinner had been delicious and they were currently eating the pie for dessert – well, Kate was eating it, he was attacking it like a mad man, stabbing at it with his fork, trying to, well –

"I'm trying to figure out a way to separate the Pumpkin from the Pi actually."

At his more or less crazy but definitely indignant statement Kate pressed her fingers against her mouth, trying desperately not to laugh at his antics but her dancing eyes, full of warm understanding and amusement gave her away.

"I hate to break it to you, babe, but the pie is made out of pumpkin, it's all melded into one."

"No!" Kate jumped a little at his loud and sudden exclamation. "No, no, no! There's Pi and then there is Pumpkin. See?" He lifted the filling from the crust, shaking his head vehemently and glancing at her a little exasperated and a lot horrified. "And I like the Pumpkin, not the Pi! Those two things don't go together."

"Since when?"

"Since… since…uh, forever?!"

She sighed a little and he watched her taking in the table decorated with little paper pumpkins, the huge plate with the pumpkin pie in the middle lovingly made by her for him, and suddenly he felt like the biggest idiot of all time.

"I'm sorry. I didn't mean to… Look, I love that you made me…pumpkin pie?" his face scrunched up comically, trying desperately not to look disgusted at the thought of his formerly beloved dessert choice. The partly amused, partly stern look she pinned him with told him he wasn't really successful.

"How about you try not to formulate it as a question the next time; you really aren't helping your cause here, buddy!" But she couldn't suppress the twinkle in her eyes and the twitch around her lips, trying to hide a smile. His shoulders slumped in relief; at least she wasn't offended. Much.

"It's just, the idea of eating Pi...it creeps me out," he whined, adding a little pout for effect.

The smile took over her face then, love and compassion shining in her eyes and she got up from her chair, sinking down in front of him and letting her palms glide across his thighs in a soothing manner.

"Hey, I understand. I really should have known how your over-imaginative mind works, - I love your mind - and truthfully…"

"Just my mind?" he piped in, waggling his eyebrows at her.

He got an eyeroll for that but she continued nonetheless, "However, as I was saying I have to admit the connotation of Pumpkin Pi is a little…disconcerting."

At his eyebrow raise she covered his mouth with her fingers, successfully blocking his sure-to-come veto of her word choice. "Ok, maybe not disconcerting. Maybe the better word would be…"

"Yucky," he mumbled around her fingers.

"Worrisome."

"Disgusting."

"Awkward."

"Brain-bleach-requiring?"

Kate scrunched up her nose in that cute way of hers, contemplating, before her gaze turned conspiratorial and she nodded, "Yeah, I think you're right." Her arms came around his neck then and she settled down on his lap, straddling him in the chair. "I think especially as her father it's only natural that you cringe a little at the thought of…"

"Don't say it!"

"Pumpkin Pi. I was gonna say Pumpkin Pi!"

"How is that exactly better?"

She tugged at his hair in retaliation, shooting him an amused smile before turning a little more serious. "Look, I promise no pumpkin pies in the foreseeable future, ok? Maybe we stick to other dessert choices like maybe cherry pie…"

She trailed off at his horrified look and the choked sound coming out of his mouth.

"Umm ok, apple pie then?"

Shaking his head vehemently he squeaked out an Apples! Not really able to say something else while desperately trying to stop the images his mind was bombarded with – one worse than the other.

"Ok, ok. Got it, no more pie. Or Pi. But Castle, I'd hate to see your favorite dessert go out the window just because of this whole…Pi debacle."

"Oh, nice. Pi debacle. I like it."

"You would. But seriously, maybe you…we should try to make an effort, hmm? Let's invite Alexis and Pi for lunch tomorrow since they won't be able to attend the big pumpkin carving contest tomorrow night. They haven't been over together since they got their own apartment. And now that Alexis and you are on speaking terms again…what do you think? Ready to try and get used to Pi in small doses?"

"Well, it's a little late for that since I had Pi-overload for a whole month."

At her stern look he added, "But you're right. I think this could be a good…idea?" She narrowed her eyes at him. "Not a question, got it. It is a good idea of course," he hurriedly added before turning serious for a moment. "I might not like Pi or think he's the best choice but…I can make an effort. For Alexis. And for the sake of my future dessert choices," he added. "But still, no more uh…pies for a while, ok?" He gestured comically at the table, looking at her with wide, pleading eyes, "Especially not this kind of pie."

"Of course, no more pumpkin pie, I promise. Thank you," she smiled at him gratefully, and a little proud. "I know it's hard, Castle, but this is part of the growing up process – for both Alexis and you."

"Me? Why me? I'm all grown up already."

She gave him a look but then her eyes took on a mischievous glimmer, and she wiggled closer to him on his lap, whispering in his ear, "Are you sure you're all…grown up?" Thrusting her hips she added, "No more…growing you can do?"

"Whoa, devious woman! I'll show you growing!" He growled in her ear, biting her lobe in retaliation before grabbing her and carrying her hurriedly to the bedroom, spurred on by her delighted laugh.

Needless to say all thoughts of Pi – or pie – were entirely forgotten.

The next day he opened his door to the smiling and slightly excited faces of his daughter and her…Pi.

"Mr. C! Nice to see you again! Thank you for inviting us for lunch." Holding out a tin foil-covered plate he proudly announced, "We even brought dessert; we made it ourselves."

Castle flicked his gaze between Pi's large grin and his daughter's beaming smile, while warily eyeing the plate. "Yeah? How umm…nice of you. What did you make?"

"Your favorite, Dad. Pumpkin pie."