"Oh—shoot!" Kate Beckett cursed (well, Mom-cursed) when she dropped her keys just outside the elevator on the penthouse floor. She was already jugging her purse, gym bag, and shopping bag, so of course she would drop her keys as well. Huffing out a breath, she squatted down, hooked the keyring with her pinky finger, and then stood back up. Thank god being a mother had taught her good juggling skills.

After unlocking the front door, Kate dropped her load to the ground and was about to call out for her family when she heard her favorite sound in the world: the cheerful giggle of her son, Jake. Smiling inwardly, she kicked off her heels and then tip-toed her way towards the office-slash-playroom, eager to catch a glimpse of what was going on inside without ruining the magic. When she'd crept to the edge of the bookcase entrance, she saw her husband and son sitting on the ground, an interesting scene of Lego buildings and action figures surrounding them. She immediately knew they were in the middle of one of Castle's story-come-to-life sessions and hung back to listen as the writer continued to craft a tale for his son.

One thing that Kate had become certain of over the prior few years was that Richard Castle was absolutely meant to be a father. From the moment they started trying to conceive he began reading book after book, article after article. Given how uncertain he'd been about having a family when they first started dating she was pleasantly surprised with how enthusiastic he was being, but still remained nervous for his parenting skills as well as her own. Those nerves evaporated the moment Jake was placed into his father's arms; Castle was a natural. He was there for every diaper change, every feeding, every time Jake awoke at 2 a.m. and decided that screaming was the best thing he could be doing at that moment; Castle never missed a beat. When she finally went back to work, he put all his writing on hold to take care of their infant, and she knew he was still happy to be the world's greatest stay at home dad three years later.

Kate lovingly observed their play session for almost five minutes before Jake spotted her, squealed out, "Mommy!" and ran charging in her direction.

"Hello sweet boy," she said as his arms locked almost painfully tight around her hips. She feathered her fingers through her hair and smiled down at him. "Did you have a fun day with Daddy?"

He gazed up at her, resting his chin against her thigh and proclaimed, "I'm hungry." Kate couldn't help but laugh; her son was always hungry—and growing. In fact, from what they'd seen so far they believed he might even end up taller than his father.

"Dinner's in the oven bud; we'll be eating soon." Castle reminded his son as he began gathering up their playtime accessories.

"Sweetie," Kate said, moving her hand to cradle the back of her son's skull. "Can you please put all your Legos back in their crate?"

Without a word, Jake ran back to the play area and began doing as he was asked. Kate then beckoned for her husband to follow her and led the way back towards the foyer to the shopping back she had dropped. Nervous butterflies filled her stomach as she scooped it back up and turned to face her curious partner. "Real quick—you wanna see the shirt I got Jake today?"

"Of course."

Smiling in the reflection of his grin, she reached down in the bag and pulled out the blue t-shirt inside. Holding it by the shoulders, she displayed it so he could read the black lettering on the front. Big Brother. She watched as his eyes grew wide and then he looked up to her with the same amount of love and devotion he had every morning they woke up together since the day she officially moved in five years earlier.

"So you're ready then? To schedule the appointment with Dr. Kleinman?"

She let out a breathy laugh. "Uh, well, I don't thinking we're going to need the appointment, actually…"

"You—what—are you—are you serious!?" he stammered out.

She bobbed her head. Mild nausea in the mornings, tender breasts, and nearly three weeks later on her cycle—all the signs were there. "Pretty sure, yeah."

"But—but—but!" He spluttered. "This is impossible!"

She arched an eyebrow at him. "Says the man who believes in Bigfoot."

"But it is! Oh, Kate!" He sighed out before pulling her into a bone-crushing hug, which she happily reciprocated.

Though she would never turn down an opportunity to tease him, her husband was right; natural conception was supposed to be virtually impossible for them thanks to various fertility challenges Castle faced in the wake of his accident. When they were trying to conceive initially, it took two rounds of artificial insemination before they had success. Their doctor had warned them that any future children might need to come as a result of IVF. After a discussion a few months prior about having more kids, Kate had gone off of her birth control and they hadn't been using any other forms of protection since they hadn't believed it to be necessary. Apparently, Mother Nature thought differently—not that she was complaining.

"So you're excited about this then? Another baby?"

"Are you kidding?!" he gushed, pulling back and giving her a long, sweet kiss. "I can't wait to have another baby with you! I hope it's a girl! Or a boy! Or both!"

Her brow wrinkled. "Both?!"

"I meant twins."

"Twins!? Oh I don't know about that, Castle."

"Why?" He grinned. "It would be awesome."

"Ah," she hesitated as the image of her belly being twice as big as it was with Jake flashed through her mind, "well it would be something, but given how unlikely it was that we got pregnant at all, I don't think you should get your hopes up for twins."

He nodded. "True, but I'm so excited Kate—another baby! I love you—so much."

She leaned in and kissed him. "I love you too, Castle."

A/N - thank you all so much for reading - I'm so glad that you enjoyed this story

Up next as promised - Between Two followed by the christmas fic It's Only Just Begun

And if you can't wait until the 17th for a christmas story, go read 2015's Christmas story Peace & Joy ;)