Disclaimer: CASTLE belongs to ABC…the song belongs to Michael Buble.

Author's note: This story has no spoilers…though it is slightly AU as I included a minor character that was unfortunately disposed of sometime in the early part of Season 3. This one is a bit of fluff to help offset the angst I am sure that is to follow with this Monday's Season 4 premiere. This one was inspired by the song 'You and I' as sung by Michael Buble – suggested by prdnanny. Hope you enjoy.

Summary: After years of dancing around each other, they had both finally given in…and Castle found himself falling even deeper in love with her with each passing day…set to Michael Buble's 'You and I"

"Have I already told you that you make a radiant bride?" Castle murmured. "I've never seen a more beautiful one."

The woman in his arms laughed as he expertly spun her out in time to the music before drawing her close again.

"You look so happy." He continued.

"I am happy, kiddo." His mother replied as she beamed up at him. "I never thought I could be this happy again, but here I am."

Castle smiled as he pulled her into a hug as the song came to an end, his eyes misting as he held her close. "I'm going to miss you." He whispered.

Martha pulled back, gently framing his face with her small hands. Her eyes shimmered brightly as she smiled fondly at her son. "I'm going to miss you too, but really, Richard, Chet and I will only be across town. It isn't the moon."

Castle laughed softly. "Might as well be."

She smiled as she lowered her hands to the lapels of his jacket. "Richard, I love you and I am so proud of the man you have become." Her eyes met his as they grew serious. "But let me give you a bit of advice…don't wait too long or you might just miss your chance."

Castle's smile softened as he nodded. "I won't, I promise." He hugged her close once more, releasing her as the leader of the band announced that it was time for the bride and groom's last dance.

"There's my beautiful bride." Chet grinned as he appeared beside them on the floor. Martha laughed as he looped an arm around her waist and drew her close. "I thought you might have changed your mind on me."

She kissed her new husband before gracing him with a beautiful smile. "Oh no, I'm afraid you're stuck with me."

"I'm afraid she means it." Castle remarked with a look of mock sympathy. He offered his hand to Chet. "Good luck to you."

The older man laughed as he took it. "Thank you. I'll take good care of her."

Castle graced them with a warm smile. "I'm sure you will."

He watched as the pair made their way out to the center of the dance floor as the band began their final song of the night. He had a feeling that this marriage would be a good one; Chet truly loved his mother and she loved him in return. Her room would always be ready for her…but he had a strong feeling that she wouldn't be needing it anytime soon. As much as he would miss having her around, he was happy for her. She deserved to be happy.

Castle shifted his attention to the remainder of the ballroom, his eyes scanning the crowd for a certain beautiful detective. A soft smile stole over his handsome face as he caught sight of her out on the terrace; he wove his way through the crowd of couples as they began to fill the dance floor and a soft tenor voice began to sing.

"Here we are on earth together…just you and I…God has made us to fall in love, it's true…I've really found someone like you…"

Castle paused at the edge of the room, captivated by the vision before him. Kate stood with her back to him, her hands on the marble railing that lined the edge of the balcony. The fabric of her strapless midnight blue evening gown shimmered beneath soft light cast from the small lanterns which hung artfully overhead. His eyes caressed her lithe frame, lingering on the flawless porcelain skin of her exposed shoulders and neck. A soft sigh escaped his lips as he contemplated how lucky he was. After years of dancing around each other, they had both finally given in…and two glorious years later, he found himself falling even deeper in love with her with each passing day.

"Will it stay, the love you feel for me…will it say, that you will be by my side to see me through…until my life is through…Cause in my mind, you will stay here always…in love…you and I…you and I…you and I."

Kate turned as she sensed his presence and Castle felt his insides turn to a warm goo as she smiled at him. He found himself wondering…and not for the first time…what he had done to deserve her. He moved forward, his eyes never leaving hers, and offered his hand; he drew her into his arms as she accepted it and began to move them slowly in time to the music. After a moment, Kate gently tugged her hand from his and slid her arms around his neck as she laid her head against his broad shoulder. Castle wrapped his arms around her slender waist as he brushed his cheek against her soft hair. His eyes drifted close as the peace of the moment washed over him.

"I am glad…at least in my life, I've found someone that may not be here forever to see me through…but I found my strength in you.."

His mother's advice rose to the forefront of his thoughts he listened to the lyrics of the song. He had no intention of letting Kate get away…or waiting much longer to make her his… He knew there was no guarantee that they would always be together. Her job was not without its dangers, however it was what she loved and an integral part of who she was…and he would never ask her to give it up for him. As long as she chose to serve the city she loved, he would stand beside her… He needed her. She was his rock…his guiding light…he had been lost before she had entered his life and had never even known it. Castle smiled as he turned his head slightly and brushed a kiss against her forehead as he cradled her closer. They had ceased dancing and were now just simply swaying to the music which filtered through the open doors.

"Cause in my mind, you will stay here always…in love…you and I…you and I…you and I."

Despite his previous apprehension, Castle knew without a doubt that Kate was the one he wanted to love forever…to grow old with. She was his 'one and done'. The ring he had carried around for nearly a month felt heavy in his pocket…and he knew there could never be a better time than now. He gently pulled back, meeting Kate's questioning gaze with a reassuring smile as he reached into his pocket. Her eyes widen as he withdrew a small velvet pouch, lowering to one knee before her as he tipped its contents into his palm. The diamond solitaire sparkled beneath the soft light and his warm eyes met hers once more, his confidence returning as he saw the answer in her eyes.

"Katherine Beckett, will you marry me?"

"In my mind we can conquer the world…in love… you and I."