AN: Here's a random one-shot that formed in my head. Don't know where it came from really. As always, constructive criticism is welcome.

Disclaimer: I don't own Castle.

Rick smiled as he sat in bed and listened to the sounds of soft humming emanating through the baby monitor on the night table. Kate was putting their one-year-old son to bed, as was the nightly ritual. A few seconds later, the humming stopped and shuffling could be heard. Rick knew that Kate was moving from the rocking chair and putting Luke into his crib.

"Good night, my little man. I hope you enjoyed your birthday today," she crooned softly, gently. However, Rick sighed as he heard a slight crack in her voice, a crack that had nothing to do with the prospect of Luke becoming older.

Rick knew that the current day was both a blessing and a curse for her. How could it not? She had experienced two major events on this day that forced her to experience an array of emotions. One of the events was Luke's birthday.

Earlier that day, they had thrown a small party for their little boy that consisted of their closet family and friends. Everyone had fussed over the youngest Castle, showering him with presents. Esposito had given him a junior detective badge, claiming that it would prepare him for later. Ryan and Jenny had bought one of those Fisher-Price toys that made various sounds and taught the alphabet. It was apparently something that their own child, Lucy, was absolutely enthralled with. Lanie had bought a teddy bear that was dressed as an ME, complete with a foam stethoscope and sewn on I.D. tag that read:"Dr. Bear". Alexis and her boyfriend had bought a giant, stuffed polar bear. It was the most recent animal that Luke seemed to take interest in. Finally, Martha and Jim had pitched in together bought a play mat that was Lion King themed. It had a mobile above it and played music if Luke moved. Of course, Rick and Kate had bought him an array of presents, one of which was a tiny motorized car that Luke could ride around the apartment safely.

The party had been a blast, and everyone had been in good humor. They chatted with one another and laughed at Luke's antics. When it was time for cake, which was arctic themed like the rest of the party, Kate helped their son blow out the candles. Luke then proceeded to attempt to trot a plastic polar bear cake decoration across the table. He had looked adorable, and Rick just had to take a picture. It was a good thing too, since a moment later, Luke dropped the bear into the cake. The little boy made a mess out of the cake trying to get the trinket out on his own. Rick and Kate just shrugged it off and laughed as they saw their son already try to become independent.

Throughout the day, Rick would occasionally glance at Kate to see how she was. He looked for that hint of sadness or mourning in her eyes. He also examined her smile to see if it was forced. If it ever happened, he would have asked her if she wanted to sit out for a while. He knew she might be a little overwhelmed and he just wanted her to be as comfortable as possible. However, she had seemed okay the whole day; although Rick could have sworn he saw a distant look in her eyes occasionally, but if it was there, it disappeared quickly. The author was drawn out of his thoughts by the sound of feet padding across the carpet.

"Hey," he said, opening his arms out to his wife.

"Hey," she responded softly, crawling into his arms. Rick then encircled his arms around her body, holding her against his chest.

"How are you?" He gently ran his fingers through the ends of her hair trying to comfort her. Kate turned her head to face him, and he could see moisture in her hazel eyes.

She shrugged. "As good as I can be. I mean, it is our son's birthday." She smiled a little, but Rick could see the sadness in her eyes coming on full force.

"It's okay; it's just us," he whispered, gently kissing her neck.

"I know, it's just," she started, and Rick could hear her swallow. "God, she would have loved him, Castle." Her voice started to crack.

"I think so too," he murmured.

"How can I be so happy and thrilled, when I should be sad?" she asked herself, shaking her head.

"It's okay to be all of them."

"I know, it's just that I feel so guilty," she whispered, looking down at her hands. Rick then gently lifted her face with his fingers and turned her head to face looked deep into her eyes, and then gently stroked her face.

"She would want you to be happy, though. She wouldn't want you wallowing all day when you should be celebrating."

Kate nodded, and chuckled softly. "She would have probably taken your side of the argument."

"Just like many other times, apparently," he teased, recalling the countless times Kate said her mother would have agreed with him.

"I did enjoy today. However, there were moments where I would I have flashbacks, just vision her in that alley. I would tried to repress them though, and focus on Luke. I would think about how even though she died today, a life was also created." She placed her head on her husband's shoulder and sighed. "I'm waiting for evidence that he's her reincarnation," she joked.

"Mmm, he might be," Rick agreed.

Kate then sighed. "When Luke was born, all my attention was on him, obviously," she said, her voice cracking. "However, once everything calmed down and I was alone, it was like I snapped. I have to admit that I cried for a bit, both from joy and sadness. I felt guilty that I hadn't given her a second thought the whole time, even though I know I shouldn't feel guilty." Kate shook her head in dismay. "My emotions are so messed up," she grumbled.

"Your emotions are perfectly fine," Rick murmured, kissing her forehead. "You're in a tough situation. It's okay to feel confused about what to do and how to feel."

"I used to just wallow for the day and visit her grave," Kate said. "However, I know I can't do that anymore. I have a child to take care of, his needs come before mine."

"We can visit her grave tomorrow," Rick said. "Also, you know what?"

"What?"

"As cliché as it sounds, I think she is here. I think she's watching over us, and she's proud of you and her beautiful grandson. She's probably watching him now, wishing him a happy birthday."

Rick wiped away the tears that had begun to roll down his wife's face. She smiled a little and gave him a kiss on the lips.

"Thank you," she murmured. "I needed that."

"Always here to help." Rick then pulled the covers over them. "Now, we should get some sleep." He wrapped an arm around her waist after she laid down on the bed. He knew she was not up for any extracurricular activities that night, so he settled for cuddling.

"Indeed," she murmured, burrowing her face into the pillow. "'night"

"Good night, Kate," Rick whispered, kissing her hair.

He knew that by morning the tears and sorrowful eyes would be gone. In their place would be bright eyes and a bright smile. His Kate would return and she would act like nothing had happened. However, he was content with just holding her for the rest of the night, glad that she let him see this side of her.

As he drifted off to sleep, Rick could have sworn he saw a figure standing in the corner of the room, a content smile on her face. Rick then dismissed the notion, chalking it up to fatigue, and fell asleep a few moments later.

AN: Okay, probably the worst idea I have ever had. Like I said, I have no idea where this came from, at all. As always, constructive criticism is welcome.