This is insanely long , about 2,000 words. But, before you read, I was wondering if you guys would be okay with the kids getting older? Just food for thought.

Enjoy!

Kate Beckett sat at her desk as she tried to make her way through her paperwork. She sighed when she looked at the time. It was only five o'clock and her brain was already starting to melt. The detective rubbed her eyes trying to keep herself from falling asleep knowing she still had another hour 'til her shift ended. The woman heard footsteps by her desk and looked up to see her partner with a huge grin on his face.

"Guess what?" He asked excitedly. She gave him a look telling him she was not in the mood to play guessing games. The man's grin grew wider.

"What?" She sighed secretly happy for the distraction.

"I just got invited to a party!" He said. Kate rolled her eyes.

"I'm not going as your date Castle." She told him not taking her eyes away from her work. The man pouted.

"Not even if you had to go as a princess?" The writer asked.

"Why would I go to a party dressed as a princess?" Kate questioned looking up at him.

"Because I," he paused waiving an envelope in front of her face before saying, "am going as a prince."

"Did you get invited to a masquerade ball?" She sarcastically answered as she tried to grab for the envelope.

"Nope! A birthday party!" Castle responded. Knowing it was not Alexis' birthday, the detective raised an eyebrow.

"A birthday party?" She parroted.

"Yep! See?" He said giving her the invitation. Kate opened the envelope and read what the paper said.

"Cassie and Lanie are inviting us to their birthday party?" She asked shocked.

"Yep!" Castle excitedly stated. She smiled.

"Why didn't I get one of these?" Kate questioned nodding to the paper.

"They didn't have your address." Castle told her before asking if she were going to the party. Kate's face lit into a bright smile.

"Of course!" She said answering the writer's question.

"Good, because I already RSVP- ed for us." He told her. Kate smirked knowing he would do something like that.

"I'll pick you up at eleven on Saturday?" He asked her. The detective nodded before going back to her paperwork. Castle looked at her for a second before sitting in his chair.

"What are you going to dress up as?" He asked.

"We need to dress up?" Kate questioned.

"Yeah, the invitation said to come dressed as your favorite Disney character or something like that." He told her. Kate raised her eyebrow before looking at the card. Sure enough, it said it was a costume party. She looked up to see Castle's eyes light up.

"What?" She asked.

"You should dress up as a princess." The writer enthusiastically told her.

"Where am I going to get a princess costume? The party's tomorrow." She stated. Castle smiled.

"We'll go shopping for it!" He told her. She shot him a look before he said, "Either that or you can wear that dress you wore a few years ago to that benefit we went to." Kate smiled at the memory of that night.

"Okay. But not that dress." She said smiling. "I think I have a dress that will work though." She said.

As stated, Castle picked Kate up from her apartment at eleven on Saturday.

"You ready?" He asked once she opened the door. She had her hair in a low pony tail, had on a blue dress with an apron over it, and black flats.

"Almost." She replied. The detective grabbed a book and the presents before stating they could leave.

"Interesting outfit Castle." Kate told him in the car as she looked at his Prince Charming costume. She had to admit, he looked dashing as a prince.

"Thanks." He told her.

Twenty minutes later, the writer and detective walked up to the porch of an older two story house. Kate knocked and the door opened to show Mrs. Sanchez dressed as Granny from Red Riding Hood.

"Detective Beckett, Mr. Castle come in!" She said cheerfully. The detective and writer smiled before asking she call them by their given names.

"Where is everyone else?" Kate asked as they walked into the living room.

"They should be here soon. You two are the first to get here." Mrs. Sanchez stated as she took their coats and put them in the other room. Castle and Beckett looked around the room noticing the toys in a basket off to the side and streamers around the room.

"Kate, Rick!" The girls said happily as they ran to given them hugs.

"Hey guys!" The adults said hugging them back. When the girls let go, Kate noticed Cassie was dressed as Cinderella and Lanie as Belle. Lanie giggled as she looked at Kate and said, "You're dressed like me!"

"Yep! But, you get to live in the castle with the prince!" Kate said smiling. Castle turned when he heard his name. Beckett looked up at him.

"Not you Castle." The woman said causing the girls to laugh. Kate quickly turned back to Lanie as Rick went back to talking to Cassie. Mrs. Sanchez came in the room to see the exchange between the adults and children and smiled before walking in the room. From the other room, a timer went off.

"Is that the cake Abuela?" Lanie asked excitedly as she followed the older woman.

"Yes mija, but you can't eat any 'til after we eat." She told her. Lanie nodded before going to watch her Grandma frost the dessert.

"We get two cakes!" Cassie told the adults, "One for me and one for Lanie!"

"Detective Beckett, Mr. Castle, I thought I heard you guys out here!" Mr. Sanchez told them as he came into the room with Corbin.

"You did dress him up!" Cassie said happily noticing her brother's frog costume. Any response was cut off by the doorbell.

"I'll go answer that." Mr. Sanchez said.

"Do you want me to take him?" Kate asked nodding to Corbin. Mr. Sanchez nodded handing the baby to the detective.

"Hi sweetie, do you remember me? You've gotten so big!" Kate told the child. Corbin cocked his head as if trying to remember.

"Lanie, Cassie!" A girl about the same age as the girls screamed hugging each other as Lanie ran out of the kitchen. Castle and Kate winced at the high pitched squeals of the girls.

"Shouldn't you be used to this?" Kate ribbed.

"Not if you haven't heard six year- olds scream in a few months." Castle told her as the adults watched the girls run off to play as they waited for other children to arrive. Kate decided to set Corbin on the floor and let him walk around.

"That's their best friend Laura." Mr. Sanchez said. Castle nodded.

"I remember when Alexis was that age. She and Buttons would do that." He said.

"Buttons?" Kate asked.

"A girl in her class. I don't know her real name. That was just her nickname. I don't think anyone's parents would be that cruel." He replied.

"Says the man who named his character Nikki Heat." Kate mumbled.

"Hey, that was creative license!" Castle protested. Mr. Sanchez smiled at the pair. Kate, feeling slightly uncomfortable, left the room to help the kids' grandma.

An hour later, Kate and Castle were standing at the side of the room watching the party. The cake had been served and now the kids were playing a game before Cassie and Lanie opened their presents.

"What did you get them?" Castle asked as he bumped his partner's arm. She smirked before replying, "Not telling. You'll have to guess. What did you get them?" Castle smiled.

"Did you get them Laser Tag?" She asked.

"No." Castle decided to answer.

"You did didn't you?" She questioned. Castle's grin grew wider. Before she could say anything, Kate noticed Corbin walking toward the cake. She quickly picked the child up and said, "Do you want a little?" Corbin nodded and said, "Cake!" Kate laughed as she gave a small piece of cake to the baby.

"You're as bad as my mother." Castle said coming up to her. Kate rolled her eyes.

"I haven't seen the little guy in months, cut me some slack." She told him before adding, "Besides, it's not like I'm his mother. I can spoil him a little. Can't I?"

"Yeah, but you were his mom for about a week." Castle told her referring to her earlier comment as he sat on a chair beside her.

"We took care of them for a week. I wasn't his mother." Kate told her partner. The writer and detective sat in companionable silence for a moment watching the party. A few moments later, Mrs. Sanchez found the pair and said, "Kate, could you help me with the piñata?" Kate smiled.

"Sure." She said handing the baby over to Castle. Kate came back ten minutes later to find Castle bouncing the baby on his knee. She smiled as she sat down. The duo looked over at the children who were now hitting the piñata. The adults were caught up in the excitement, they did not see a woman come take a chair beside them.

"Your son is adorable." The woman said to Castle who was still holding the boy. The writer and detective turned to the woman.

"Which child is yours?" The woman went on. Castle cleared his throat while Beckett said, "None. We're friends of the family."

"I'm sorry, I just thought—" The woman started before Castle said, "It was an honest mistake."

"He just looked like he could be yours." The woman stated. Beckett smiled as Castle set the child down.

"No," Kate said ruffling the boy's hair. "He's not." The detective answered softly.

"Kate, Rick!" Lanie screamed coming up to the adults, "Look how much candy I have!" The adults looked at the candy.

"That's a lot!" Castle commented enthusiastically, "Did you leave anymore for the other kids?" He joked. Lanie rolled her eyes, "Yes." Was the girls reply. The adults smiled as the girl ran off. The duo turned to see the woman talking to her own child before looking at her watch. Kate looked over at the girls who were sitting among other kids. Kate and Rick walked over to the group to watch the girls opening their presents. After a few were opened, the detective turned to see the writer's face light up. She smirked as she turned back to the girls.

"Laser Tag!" The girls screamed excitedly. Jumping up, Cassie and Lanie ran to hug Castle. He hugged them back.

Half an hour later, the guests began to leave. Kate noticed this, and went to help Gloria clean up.

"You don't have to help." Gloria told her. Kate smiled at the woman saying, "It's fine. I think Castle has the kids entertained for a bit anyway." The women looked out of the room to see the writer getting laser tag set up for the kids. Laughing, the women went back to throwing away paper and cups.

"How old is his daughter?" Gloria asked. Kate looked up.

"Alexis?" She questioned. "She's eighteen." Kate responded. Gloria nodded.

"It's always hard when they leave." The woman stated. Kate, not knowing how that felt, nodded.

"You'll understand one day." Gloria stated. Kate smiled.

"Thank- you." She responded wondering if the woman were right. The women finished and went toward the girls.

"They having fun?" Kate questioned Rick causing the man to turn.

"Yeah, tons." He responded smiling.

"It's getting late. We should probably go." Kate told him.

"So soon? But, the girls are having so much fun!" Castle responded. Kate rolled her eyes knowing her partner was having fun too. Kate gave the man her signature look causing the man to frown.

"Fine." He said sadly. A few minutes later the duo was at the door.

"Wait!" Lanie said running toward them, "You forgot a gift bag!" The adults smiled as they took one before hugging the girls again.

"Ready Detective?" Castle asked once they were outside. She smiled before replying, "Lead the way Writerboy."

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