"Mackenzie. Mackenzie, wake up. It's time to get ready for your party.'" Kate gently shook Mackenzie's shoulder until her eyes flickered open. She had dark circles under her eyes and she was deathly pale, but the sparkle returned at the anticipation for the coming event. Kate helped her wash and change into a new dress.

"Lexi and I found it today."

Alexis helped set out the decorations while Kate finished helping Mackenzie dress. Soon Esposito, Lanie, and Ryan arrived bearing presents and birthday wishes. A few minutes later, Martha dropped off Aiden, who had brought his video camera to capture the party. On her way out to her show, Martha motioned for Kate and whispered to her, "The clown will arrive in about 10 minutes."

Kate hugged her tightly. "Thank you, Martha. You're the greatest."

She winked. "A small repayment for the kindness you've shown us over the last couple of days kiddo."

Everyone enjoyed themselves at the party. Mackenzie loved seeing her Aunt and Uncles. The clown kept her smiling the entire hour, and he made her several balloon animals. Besides juggling and telling jokes, he pulled Aiden into the center when he realized he liked to do impressions. Together they had everyone crying with laughter.

Then, Mackenzie had blown out the candles on her cake. 5 years old. She made it! Everyone thought her birthday wish was to get better, but she shared a secret look with her mom after the candles went out. They both knew Mackenzie's greatest desire was to have a dad.

She loved her mother, but she also dreamed of a dad who would tell her stories, dance with her and maybe even sing her to sleep. She also wanted someone who could take care of her mom. Kate showed her cheerful face around other people, but sometimes late at night when she was supposed to be sleeping, Mackenzie caught Kate crying. She wanted someone to take care of her. Mackenzie stopped daydreaming about her party and wish to catch the end of the story. "The handsome prince kissed the princess, breaking the spell and they all lived happily ever after."

Kate closed the gook and gave both Mackenzie and Alexis a squeeze. "All right you two, twenty more minutes, then it's time to get ready for bed."

Rick had arrived at the activity room in time to hear the end of the story as well. He decided to wait outside the door until they finished, since he loved seeing Kate interact with his kids. Alexis smiled and played when Kate was near, but her conversations with Aiden really gave him a new appreciation of her. He watched Kate walk over to Aiden. "How's that homework coming?"

Aiden didn't look up, but mumbled as he continued to stare intently into his math book. "Almost finished."

Kate muttered uh huh and reached over to pull the Spider-man comic out of its hiding place in the chapter on multiplying fractions. "Hey!" he protested.

"Not another word, mister. If you've got this much free time, you can help me on my rounds; it's time to clean the bedpans."

Aiden's eyes widened, disgusted. "No way, Kate! That's gross! Besides, I need to study for a math test tomorrow."

Kate nodded. "Okay, then see that you do." She winked at the girls then grabbed a duffel bag and pulled a privacy curtain to change her clothes. A minute later, she emerged in her scrubs. She turned to Aiden before heading out the door. "I'm going to quiz you when I return." Turning, she almost ran into Rick in the doorway, exclaiming a little "Oh! Hey Castle."

"Hi Kate, I hope the children weren't any trouble."

"No trouble at all, but Aiden and I have a fractions quiz when I return." She glanced around at him and saw him bury his head into his math book. Rick tried to let Kate pass by stepping aside, but Kate stepped the same way. They both muttered sorry and stepped aside, again right in front of each other. When the same thing happened a third time, they heard giggles from behind them. Rick grinned and winked at Mackenzie and Alexis, then bowed slightly at the waist and neck.

"Shall we dance, Miss Beckett?" Rick stuck one hand out to her waist and held the other up. "A waltz, perhaps?"

She hesitated a moment and looked him suspiciously in the eye, and then took his hand. "I'd love to Mister Castle."

Rick hummed a couple bars of music then led her around the room, spinning to avoid hitting chairs, tables and toys. Kate had never danced with someone this skilled before. She felt like she was floating on air.

After twirling her once, he heard Alexis call out. "Waltz's are boring, Daddy. Do the Mambo!" Rick paused a moment and looked the question at Kate. She shrugged. Just then, Aiden started singing a tune with the appropriate beat and the girls joined in. Kate and Rick smiled at each other. They danced around the room again, this time really feeling their bodies moving in sync to a more sensuous dance. They paused as Rick twirled her in, flush against his body. The kids clapped.

"Mama, how about the Cha Cha?" Mackenzie called out her preferred dance in a weak, but happy voice. Kate stepped away and looked embarrassed at Mackenzie's request.

"Oh, I don't know honey. Maybe Rick doesn't dance the cha cha."

Rick stepped back, acting wounded, placing his hand over his heart. "I'll have you know that I do know how to dance. I can even boogie all night if you want to."

Aiden snickered at his dad's terminology. "Yeah, right, Dad. You're really hip."

Rick glared at his son for a moment, then turned to Kate holding out his hand. Simultaneously, they assumed a pose at the same time. Kate counted it out and they matched each other step for step. They finished as Rick dipped her.

He couldn't help grinning from ear to ear, matching Kate's excitement, as her eyes sparkled. He glanced down at her mouth, and his smile faltered as he thought again what it would be like to kiss her. She noticed his look, and she felt her cheeks flush as they stared at each other, both of them feeling a thrilling current pass between them.

The sound of their children's applause pulled them apart and Rick turned away embarrassed, tugging to loosen his collar.

Kate wiped at her forehead with the back of her hand. "Wow, Castle, that was fun! I haven't danced in a long time." She turned to the children. "And you all were great DJs. Where did you learn so much about music?"

Aiden rolled his eyes. "Kate, we're kids. We don't live under rocks. We learn about music in school."

They laughed and Kate glanced up at the clock. "Oops, gotta run. I'll be back in a few minutes." She trotted out the door, while Rick greeted his children. Then he wheeled Mackenzie out with Alexis and escorted them all back to the girls' room to get them ready for bed.

Rick placed Mackenzie into bed, squatting down to talk with her. "So, how's the birthday girl? Did you have a nice party?"

Mackenzie's face lit up as she recounted every detail from the afternoon and even convinced Aiden to reenact some of his impressions. "We had Chinese take-out and chocolate cake. The food is gone because Mama gave it to her friends, but we saved you a piece of cake." She pointed to the bedside table.

Rick thanked her and reached into his pocket, pulling out a small box wrapped in silver paper and a bright pink bow. He handed it to her. "Happy 5th birthday, Mackenzie."

Mackenzie unwrapped it slowly so she wouldn't damage the paper and opened the box. It was a heart-shaped locket. She used her fingernail to open the locket and found the picture of her and her mom inside. She looked at Rick as he pulled the original out of his wallet and placed it back in Kate's purse. He leaned down and whispered conspiratorially. "I swiped it when your mom wasn't looking and made a copy."

Mackenzie tried to sit up, lifting her arms to put it on, but stopped midway and closed her eyes against the pain. She handed it back to Rick. "It's pretty. Will you help me?"

Rick smiled at her and gently reached around her neck to close the clasp, then kissed her on the forehead. "You've had a busy day. You should rest now." He stood and pulled the curtain halfway shut.

"Rick?"

"Yes, Mackenzie?"

"Thank you for my gift. You're a great dad." She smiled weakly, and then closed her eyes with her hand clutching the locket.

Rick stared at her for another minute, and then turned and whispered to his children that it was time to go. He promised Alexis that he'd be back later and reminded her that she would be able to go home in the morning. Tucking her in, he kissed her goodnight. As they headed for the elevator, Kate came around the corner and stepped in beside him.

"Don't worry about Alexis, Castle. I'll watch her."

Thinking about all he'd seen and heard this evening, he decided to take risk. "Kate, would you ever consider trading in your hospital career?" At her confused look, Rick quickly continued. "I'm in desperate need of help and my children already adore you. Think of it like being my assitant."

"That's funny Castle," She laughed looking at him, stopping suddenly when she realized he wasn't joking.

"Oh, you're serious." Kate eyed him a moment. "Hhmm. That's a pretty big decision, but I will think about it. How did your meeting go?" Kate asked, desperate to change the subject.

"Quite well, thank you. We're finally ready for the book launch party."

Kate turned to Aiden. "I bet you'll get all dressed up."

Aiden meekly answered. "Well, I'm not really going..."

Kate turned to stare incredulously at Rick. He cleared his throat nervously. "Actually, since someone faked his own gruesome death and scared away another sitter, we will be attending the premier as a family. Aiden and Grace will have to sit with Paula while I do a few signings."

Aiden looked horrified at the prospect of spending an evening with Paula. After some quick thinking, Aiden turned to his father. "What about Kate? I'm sure she's never been to a book launch party before and she could sit with us."

Rick glared at his smirking son for setting him up like this. Yet, the idea was quite appealing. The thought had crossed his mind several times that day, but he hadn't the courage to invite her without an ulterior motive. He decided to take the opportunity and turned back to Kate. "What do you think, Kate? Would you like to attend the launch of my new book Friday night?" He leaned in and whispered, "It's a mystery with an interesting case..."

"I don't know..." she began, but at seeing Aiden's crestfallen look, she started to laugh. "Oh, look at that face. Let me see if I can arrange it something with Lanie."

Aiden started jumping up and down, cheering, before Rick shushed him and herded Aiden into the waiting elevator. Before he could enter, Kate gently tugged on his arm. He turned back to see her eyes glistening with unshed tears. At his questioning look, she whispered quietly, "Thank you for sending the clown to Mackenzie's party. You made her day. It's the kindest thing anyone has done for us in a long time."

Rick started to deny it, but was stunned to silence when she reached up to kiss his cheek. She leaned around him to wave goodbye to Aiden and stood smiling as the door closed.