Castle's thoughts on the day his son is born. Set in the near-ish future. Castle and Beckett are married and have a three-year-old daughter, Atalie (which is pronounced like "Natalie" without the "N"). Just something random that popped in my head! Hope you like it!

Richard Castle was a father. Again. For over two decades, he'd been the father to his wonderful first born, Alexis, and he counted himself lucky everyday to have her. Alexis had prepared him for almost everything by the time Atalie was born. The only thing he hadn't been prepared for was the fact that Atalie was Kate's daughter, too, and therefore just as remarkable, maddening, challenging, and frustrating. Even still, he'd felt confident that his years raising Alexis – and in all honesty, Alexis raising him – had equipped him with enough knowledge for his second time around the parenting block with little Atalie.

But today, Castle was starting an entirely different journey. Today, his son was born. 8 lbs, 5 oz of perfect had arrived into their lives so quickly, they almost didn't make it to the hospital in time. It was thrilling to finally have their newest addition to the family, but at the same time, all too terrifying for Castle. He'd never had a son and he'd never had a father. His entire life consisted of women and he had been quite comfortable with that. He didn't know the first thing about raising a son and he suddenly felt under qualified for a role he must play.

Castle paced the length of the hospital hallway, his thoughts preoccupied with just how horribly he might screw up his son, when the sight of a certain brunette three-year-old stopped him in his tracks. There was his Atalie hand-in-hand with her grandfather Jim as they walked from the opposite end of the hall.

"There's my girl." Castle called to her. Atalie's face lit up and she broke free from her grandfather to run the rest of the distance to her dad. Castle scooped her up and hugged her tightly.

"Do I have a baby sister?" Atalie asked. Castle smiled, glad that Jim was able to keep the secret. He turned to his father-in-law.

"Kate's in that room if you want to go see her. I'm going to talk to Atalie first."

Jim grinned and disappeared into the hospital room, leaving Castle in the hallway with his youngest girl.

"Daddy, is the baby here?" Atalie asked, her head whipping around, searching for the babe.

"Atalie, you have a baby brother." Castle told her, smiling from ear-to-ear. "Do you want to see him?"

Atalie's hazel eyes grew rounder and she nodded her head vigorously, too excited for words. Castle shifted Atalie to one arm and began to walk towards the nursery. He stood in front of the window and pointed. "See that baby right there? The one in the back that's wiggling around like crazy?"

Another excited nod from Atalie.

"That's your baby brother."

"What's him name?" Atalie asked.

"His name is Harrison Richard."

Atalie's little nose crinkled up. "Harrison?"

Castle stifled a laugh at Atalie's comical expression. "Yes. What's the matter with that?"

"I like Wyatt." Atalie told him. Castle was glad Kate wasn't there for Atalie's comment. Wyatt had been one of Kate's favorite names through most of the pregnancy. Harrison had barely won out in the end, with Kate's stipulation that the middle name be Richard.

"Why is he in there? Why can't we hold him?" Atalie asked, barely taking a pause between questions.

"Just wait, Munchkin. You'll get your chance to hold baby Harrison." With that, Castle turned and strolled back toward the room. "Do you want to see Mommy?"

"Yes!" Atalie shouted. Castle smiled and pressed a kiss to her soft cheek. After looking at Harrison, Atalie suddenly seemed huge and Castle wondered how she'd gotten so big. Last week she still seemed so bitty. He shouldn't be so shocked since Alexis had grown faster than he could say onomatopoeia. It hadn't seemed so long ago that Alexis had been the age Atalie was now, and yet his oldest was almost 24.

Castle entered the room and struggled to keep a good grip on Atalie when she tried to scurry out of his arms on her own. "Easy, Munchkin." He planted her feet on the ground and turned her loose.

"Hi, Baby Girl." Kate was all smiles at the sight of her daughter. She reached over and pulled Atalie onto the hospital bed.

"Take it easy, Katie." Jim cautioned.

"It's fine." Kate shrugged it off. "Isn't that right, Atalie? We're fine."

"Yeah." The little girl smiled adoringly up at her mother. Castle took in the sight of the two. His girls, always causing trouble. Kate dropped a kiss to the top of Atalie's head and listened intently to the stories that tumbled out of the excited three-year-old's mouth. Jim was hanging on every word, too. It was easy for anyone to see just how greatly this girl was adored so Castle was feeling a little relieved she'd have someone to share the spotlight with now. Although Alexis had turned out alright as an only child, he feared Atalie's quasi-only-child status was starting to spoil her. She might struggle with the change at first, but in the long-run, it would be good for Atalie to have a brother around.

By the time baby Harrison was brought back into the room, Martha and Alexis had arrived, too. Castle felt pride swelling in him as his family embraced their newest member.

"Oh, he looks just like Richard did when he was born." Martha gushed as she cradled the baby in her arms. "What a handsome little fellow!"

"He's got Katie's hair, though." Jim interjected with a smile being sent his daughter's way.

Atalie was only amused with Harrison for about five minutes before she started to feel the dynamic shift in the family. She crawled back up by her mother, whose side she had left once Alexis had entered. Now feeling neglected, she snuggled with Kate, who was all too happy to share some restful moments with her daughter.

"Alright, Gram, enough with hogging the baby." Alexis teased. "It's my turn with my brother."

"Fine. He's getting heavy." Martha agreed, carefully passing Harrison over to Alexis. By now, Alexis was a seasoned older sister. Although she hadn't been too keen on the idea when Kate was pregnant with Atalie, she had come around by the time her sister was born. Now, Alexis was arguably Atalie's favorite person and it was quite evident that the feelings were mutual. Alexis seemed very fond of Harrison already.

By the time the family had left and Alexis took Atalie with her for a sister slumber party, Lanie and the rest of the gang were arriving to meet Beckett's new man. Everyone had loved the moment when Ryan, who was a proud father himself now to a one-year-old boy, had tried to pass the baby to Esposito.

"No, man, I don't hold babies." Esposito had said, evoking laughter from the group with his expression of fear.

"Come on, Esposito, babies don't bite… much."

"Ryan, leave him be." Kate cut in. "I'd rather not have my son dropped on his head today."

More laughter echoed in the room. Their friends from the 12th precinct didn't stay too long and as the exciting day drew to a close, it was just Rick and Kate enjoying quiet bonding with little Harrison.

"We do a pretty fantastic job making these." Castle gloated as he paced around the room with Harrison, keeping his steps light and bouncy, lulling the boy into sleep. A slow, easy smile crept across Kate's face. She loved how wonderful he was with his children, how naturally he took to them. She had practically been able to see him falling in love with Atalie and Harrison, the all-consuming love that shown from his tender expression the first time he laid eyes on them. She was sure it had been the same when Alexis was born, too. Yes, Castle loved his children with his whole heart and soul, and witnessing that had caused Kate to fall more in love with Castle than she would have thought possible.

"Yes, we do." Kate agreed. She was so enamored with her son, felt so unbelievably lucky that he was hers. How had they gotten so lucky to have these two amazing little creatures as their own?

She was in the midst of such light-hearted thoughts when she took her eyes off Harrison and was startled to see her husband's expression was so pensive. "What are you thinking about, Rick?"

He looked up, startled now himself, and then almost looked guilty. "Nothing."

"Rick." She said his name slower, heavier. "What is it?"

He sighed, seeing he wasn't getting out of this. He lowered himself into the chair next to Kate and leaned back a little. He shifted Harrison up onto his shoulder and felt the babe's breath against his neck. "I just… I don't know what I'm doing, Kate."

Her brows furrowed in confusion. "You don't know what?"

"I don't know how to raise a son. I had a mother growing up, that was it."

Kate's gaze softened. "You don't think I felt that way when Atalie was born?" She pointed out. "I was a new mom and I didn't have my own mother around for advice."

"I know," Castle murmured. "I know it wasn't easy for you, but it was different. You had years-worth of memories of your mother." His hand started to rub a slow circle on Harrison's back. "He's just so perfect. I don't want to let him down. It's a miracle Alexis turned out so great considering she had me and Meredith as her parents. The only reason Atalie –"

"Oh, Rick, stop." Kate said louder than she intended. Her eyes flitted to Harrison, but he never stirred. "It's not at all a miracle that Alexis is such an intelligent, kind, and determined young woman. You're a great father. You raised her well. And you'll keep being great with Atalie and Harrison, I have no doubt." His eyes finally met hers and he couldn't believe the amount of love her eyes held for him alone.

"Do you know why I wanted Harrison to have your name?" Kate asked him. Castle smiled boyishly in the way he did when he wanted to mask his issues with humor.

"Because you're madly in love with me?" He teased.

"Because you're the best man I know." Kate told him straight-faced, not even for a moment letting his humor dash the message she was trying to convey to him. Castle didn't take the compliment lightly. Kate was an excellent judge of character and she worked with some of the finest men Castle had ever met. His smirk was gone and in its place a look of gratitude for this woman.

Kate smiled again, seeing the effect of her words. "And because I'm madly in love with you."

Now it was his turn to smile, a real smile that reached his eyes.

"You know, I've never raised a son either." Kate pointed out with an amused expression. "But I figure between the two of us, we'll figure it out along the way."

He shook his head, wondering what he'd do without her, this fearless woman that balanced out his world so perfectly.

"And you've got about three more seconds with our boy and then it's my turn." She teased. He chuckled, pressed a kiss to Harrison's head of dark hair, and then gave him to Kate.

"There's my guy." Kate crooned. She settled him on her chest and stroked his feathery-soft cheek with her thumb. "God, he's perfect. We really do a great job of making these." Kate murmured.

"That's all I'm saying." Castle beamed.

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