Disclaimer: I don't own Castle.

Prompt: Since Stana Katic mentioned at Paley that Kate's favourite colour was purple and then "Start Wearing Purple" was a song on one of her ATP playlists, I felt that this had to happen.

A/N: The song is cracks me up like no other - you can find it on youtube or I posted the song on my tumblr (itsallblackandwhitemoviestome) as well. Finally, thanks to HPfan1952 for reading this over.

Start wearing purple wearing purple
Start wearing purple for me now
All your sanity and wits they will all vanish
I promise, it's just a matter of time...

- Gogol Bordello, Start Wearing Purple

Castle picked up the microphone with a wink for his bride, "I have a special song for our first dance as husband and wife." His voice was soft as he continued, as if speaking only to Kate, "You have memories of your parents dancing to this song, you dance to this song when you make dinner and of course...we all know purple is your favourite colour."

Kate nodded in agreement, a wide smile lighting up her face as she knew instantly what song he was talking about.

"Now, this song was written for the guy's girlfriend. When they argued and she would start screaming at him, he would warn her that she would turn into the crazy old lady that lived across the street and who wore nothing but purple." He paused for dramatic effect before continuing, "This song is also thought to be a reference to a poem called "Warning". The poem imagined that when you are old and crazy you can do whatever you want, and that includes wearing nothing but purple from head to toe."

Jim leaned over and whispered to his daughter, "He really put a lot of research into this didn't he?"

Kate only smiled wider and shrugged, "He's a writer." My writer.

"So, Kate, I look forward to spending the rest of my life with you even when, or especially when, you are a crazy little old lady who wears nothing but purple." He lowered his already deep voice, "Soooooo, start wearing purple..."

There was a tinkling of cutlery tapping crystal glasses and he pulled a laughing Kate from her seat for a long crowd-pleasing kiss.

The music began and Castle drew her out onto the dance floor, skirts swirling about her.

They twirled and swayed, trying their best to dance to the unorthodox song Castle had picked.

Kate leaned in close, "How are we even supposed to dance to this Castle?"

"Same way you dance in the kitchen."

"We look ridiculous."

"Ridiculously in love."

Kate swatted his chest, "Cheesy much?"

"Hey, it's my wedding; I can be as cheesy as I want."

"It's mine too."

"Good."

"Good."

"Fine."

"Fine."

He captured her upturned mouth in a quick kiss before he let go of her, stomping and clapping.

Kate rolled her eyes and went along with him, picking up her skirts to reveal her bright blue shoes as she twirled and stepped around him.

The song ended and they were breathless and flushed, as much from the dance as with excitement. The small crowd of family and friends surrounding them roared and cheered. Whistles echoed and glasses were clinked again for another kiss from the happy couple.

The DJ called for the father daughter dance and the slow, beautiful Blower's Daughter spilled from the sound system.

Jim and Kate chatted as they danced, Kate throwing her head back every so often to laugh. Castle smiled at the sound, his heart feeling like it would burst, and Alexis smiled back, happy for her father.

Other fathers, daughters, mothers and sons joined them on the dance floor. Alexis was standing on her father's shoes while they danced when Martha cut in to dance with her son. Jim took a turn with Alexis while Martha and Kate watched from the side, arms around each other's waist. They felt complete; a family.

The rest of the night sped by in a flurry of dancing, pictures and cake. In wasn't until the wee hours of the morning that Kate and Castle took to the floor in their final waltz. With Kate's steady hand at his shoulder and his warm hand at the small of her back they moved around the dance floor, alone in their own little world despite of the diminishing crowd.

When they came out of their misty dream world of a dance, they thanked their guests as they left the ballroom, hands clasped and waving even as the catcalls and whistles from Ryan and Espo rang behind them.

Kate leaned against him in the elevator, sleepy from the late hour and from the lack of sleep the night before due to sheer excitement.

"So, good day?" Castle brushed his lips across her hair that was frizzing lightly now from the dancing.

"Mhmmm…" She closed her eyes, just for a second, reveling in the feeling of his arms around her and the beat of his heart beneath her cheek.

"You going to stay awake long enough...?"

"Mhmm…" She nodded into his chest, which was answered with a rumbling chuckle.

Castle, with Kate still by his side, sang their song in a low whisper into her ear as he unlocked the door a few minutes later.

Kate lifted her face to catch his gaze and turned on her seduction, sleepy as she was, "I already am."

Castle picked her up to carry her over the threshold; as clichéd and cheesy as it was, it was still their wedding day. He looked her up and down, from the white dress to the blue shoes that peeked out beneath the skirts, before realization finally dawned on him, "Oh…"

The burning look in his eyes woke her up completely and she grinned as he covered her mouth with his own.

It was a song, and a night, that they weren't ever going to forget.

A/N: Leave a note and let me know what you thought of this...or what you thought of the song ;)