A/N: Well. We kinda knew it was bound to happen.

Enjoy!

Kate ties the belt of her dressing gown around her waist and sits down at her vanity. She pulls her hair from the messy updo she'd thrown it into so it didn't get wet during her shower and quickly runs a brush through it and then twists sections through her curling iron to fix up the waves she had put into it that morning. It was Date Night and she desperately wanted to look like she hadn't just endured a thirteen hour day at work.

Through the mirror, she sees a figure appear in the crack of the partially opened door; a nose and an eye peeking through, seeing if it is safe to enter.

"Come in," Kate smirks, and the door slowly opens, revealing her youngest daughter. She watches the girl shuffle across the tile. "Pick up your feet," Kate reminds through the mirror, putting lotion over her face and upper body.

Finn heeds her mom's words and her next few steps are less shuffle-like and a more toe-to-heel, proper gait. She stops at the vanity chair, leaning against the back, smiling at her mom through the mirror.

Kate looks back, admiring the girl for a moment: her smile and chipped nail polish and auburn hair, so much like her own, pulled back into a neat ponytail; she seems so much bigger in that second than she had in awhile and it surprises Kate. "Hey, you," Kate smiles. "How are you?"

"Good," Finn shrugs, eyes turned on the floor, face neutral; not her usual perky self.

"Come here," Kate directs, helping her daughter to sit on the lower countertop. "I feel like I haven't seen you in days," she says, meeting the girl's eyes. "Here, your glasses are dirty, let me have them," she says, reaching for the girl's pink frames. She runs the lenses under her towel, holding them up to the light to make sure they're clean before handing them back. "So, how was choir practice today? Did you try out for that solo like you were telling me you might?"

"Yeah," she smiles, starting to look more like herself. "Ms. Martin took us into a practice room by ourselves and we sang it for her and she said the list would be posted on Monday."

"Well I'll keep my fingers crossed," Kate smiles, opening a jar of foundation and pouring some onto the back of her hand.

"I don't think I'll get it though," Finn says. "Audrey Brewster tried out too and she's the best; she'll probably get it."

"Oh, I think you have a good chance of getting it," Kate encourages. "I heard you practicing and you were really good; so don't lose hope just yet."

"Yeah, I guess."

They sit in silence for a few minutes as Kate continues to apply makeup, Finn's feet drum against the cabinets as she watches.

"Want some?" Kate asks, holding up the pan of blush, off her daughter's nod, she pats some onto the brush and onto the girl's cheeks. Finn remains quiet and when Kate pulls back, she sighs and opens her mouth to speak.

"Momma? Did you have a nickname when you were little?" Finn finally starts.

"Yeah," Kate nods. "My mom used to call me Katie Bug, and you know Papa likes to call me just plain Katie, and he used to call me Katie girl. And then when I was in high school my friends called me Bex; I thought I was cool," she says. Finn doesn't say anything, just thinks for a while; Kate returns to fixing her makeup.

"I don't wanna be called 'Nemo' anymore," the sentence was whispered; so quiet, Kate wasn't even sure it had come from her daughter's mouth.

"What?" she asks, making sure she heard what she thought.

"I don't wanna be called 'Nemo' anymore."

"Why? Were the kids at school teasing you? Because if they were, I can talk to people about it."

"No, they weren't. I just want a different nickname."

"But you've been 'Nemo' since you were a baby," Kate says, still in disbelief.

"Yeah. It's a baby name. I'm not a baby anymore. And I know Alexis gave it to me and it's special and everything, I just don't want it anymore."

"Oh, Finn," Kate says, a sullen look crossing her face.

"Don't be mad, momma!" Finn says quickly. "Please don't!"

"No, baby, I'm not mad," Kate says, cupping her daughter's face. "I'm just sad. You and your siblings are growing up. And becoming your own people. It's such a good thing, it just makes me sad because I'll always think of you as my babies." Kate smiles, looking at her daughter; the last of her baby fat still on her cheeks, a tiny face so much like her own. "Okay," she starts, "if you don't want to be called Nemo, what do you want your nickname to be?"

"Just Finn," the girl says. "Or 'Fi', Grace and Kayla says it a good nickname too."

"Fi," Kate says, testing it out. "Okay, I think I can get behind that," Kate smiles.

"Really?" Finn asks, hopeful, smiling for the first time through their conversation.

"Really," Kate nods. "It might take some time, but if it's what you want, we won't call you 'Nemo' anymore."

"Thank you, Momma!" Finn shouts, sliding off the counter and throwing her arms around her mom.

"You're welcome," Kate says. "Now, I think I just heard you pizza get here. Go get some before you brothers eat it all." Finn leaves the bathroom, a new spring in her step, and Kate, slipping into pensive thought, finishes getting ready.

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In the lull between the waiter taking their order and their next conversation starting up, Kate brings up the conversation she and her daughter had earlier that evening. "Finn doesn't want to be called 'Nemo' anymore."

"What?" Castle splutters over his drink. "Why? When did she tell you this?"

"Earlier today when I was getting ready. It looked like it had been on her mind for a while."

"But why? It's always been her nickname."

"I know, and I told her that," Kate agrees. "But she says it's a baby name and she's not a baby anymore. She wants a more grown-up nickname."

"Like what? I don't think we have ever called her anything besides Finn or Nemo ever in her life. Everyone knows her as that!"

"I know," Kate says. It was a huge change, but her daughter wanted it. "She said just use her full name. Or she suggested one that her friends seemed to like: 'Fi'"

"Fi?" Castle asks. "Seriously?"

"Castle! It's what she wants. She just wants to be seen as more grown up. I mean they are going into fifth grade next year. And it will make her so happy."

"I know! But she's Nemo! It's gonna be hard for me to call her something else."

"And I told her that. But I also said we'd try."

"And we will," Castle agrees. "It's just gonna be weird not calling her 'Nemo' anymore."

"Yeah, it is," Kate nods. And then, the waiter arrives with their food.

[] []

The next morning, Castle oversaw the kid's getting ready for school while Kate slept in for a change. He made sure they all brushed their teeth, ate breakfast and had their backpacks packed before they had to leave to catch the bus.

"Wow, Finn! Don't you look pretty today!" he said when his daughter entered the kitchen. He made sure to put extra emphasis on using her name, hoping to show her he was really trying to not use her old nickname

"Thank you," Finn smiles, tucking her hair behind her ears.

"Always," her dad smiles back. "Come get some food," he directs, watching as she sits at the table and pours herself a bowl of cereal. Forty minutes later, he's making his wife her morning coffee when the kids leave for the bus.

"Bye, Dad!" Liam calls on his way out the door.

"Bye, Buddy! Have a good day!" Castle says.

"Bye, Dad! Love you!" Finn says, stopping in the kitchen as she follows her siblings.

"Bye, Fi! Love you too! Have a good day."

"I will," Finn says, pausing to hug him on her way. "And thanks for using my new name. I really like it."

"I'm glad you like, baby," Castle says, hugging his daughter back. And a minute later, she's out the door off to school.

He knew it would be hard to not call his youngest daughter by that famous nickname anymore; knew there would be some slip-ups. But to see the smile on Finn's face when he'd made an effort that morning, gave him the drive to keep that smile on her face.