Based on a comment on Twitter, when did Castle buy Beckett the ring? Set after Still and totally ignoring the Squab and the Quail.

Marry You

Castle left the loft in the early hours of the morning, he'd left Kate sleeping in their bed, her limbs splayed out around her, her hair a tangled mess and her bare foot poking out from the edge of the duvet. He'd run a hand down her lean arm and stolen a kiss from her slumbering mouth as he'd slid out, away from the warmth of her skin. The gentle sigh and soft murmurs from her dreams had almost called him back in, but he was on a mission. He'd given her one last wistful look before tiptoeing out of the loft, his traitorous mouth giving away his joy to everyone that he passed on the street.

The bounce in his step could not be concealed as he weaved between the oblivious citizens of the city, their faces were serious and focused as they marched on, like drones. Castle danced between them, his feet bouncing on the concrete as he held in the urge to skip through the streets. Instead he hummed as he moved, his entire body a joyful vibration radiating colour into the grey streets. His body moved in time to his humming and before he knew it, he was swinging around a lamppost, words leaking out his mouth.

"Hey baby, I think I wanna marry you".

He stopped in the street, his back straight and his eyes wide as his broad hand covered his treasonable mouth. He glanced around, his eyes searching conspiratorially for anyone that may have overheard him. When he was convinced his slip had gone unnoticed he chided himself internally, remembering her sleeping form filling his bed unable to hear his confession.

Castle had known for a while that he was going to marry her, that their fates were so intrinsically entwined that they would have to stay together or risk some terrible consequence from the universe. But yesterday, reliving their lives together as she stood on that bomb, he knew it was time. He knew that she was ready. He'd been ready for a while, he was just waiting for the moment his partner, his lover, gave him a clear sign that she was too. He'd seen it yesterday. When she called him back, bidding him goodbye, making her last words to him a vow of love, he'd seen it in her eyes. The pale specks in them screaming for him to never leave her, whilst the shimmering tears had fought to protect him. As they'd stared into each other, the last seconds of the timer counting down, he had seen into her soul, seen the hopes and dreams she hid there. Moments later she'd confirmed it, her hands twisting in his hair, smile open and wide, just for him, she'd told him.

"I think we're just getting started".

Then later that night, the third sign – because Castle knew that good things always came in threes. She'd lain beneath him, her skin glowing with the aftershock of her orgasm, their bodies pressed together until he couldn't tell where one of the them ended and the other started. She'd whispered in his ear, her face pressed into his neck, shielding herself from his all knowing eyes.

"Stay with me". It had barely been a whisper and he wasn't convinced she'd actually said it, not putting it past himself to have imagined it. He'd gathered her closer, if that was even possible, within the maze of their naked limbs, and dropped kisses through her hair.

"Always" he'd promised her.

When she'd fallen asleep against him, feeling the soft breaths blowing across his chest where she was nuzzled, he had known. It was time.

So he'd snuck out of their bed and was on his way to find the perfect ring, one that would capture the essence of her, and if he couldn't find one that did that, then he would look for the prettiest, shiniest ring he could find.

He'd, somewhat unrealistically, expected the universe to celebrate with him, expecting blue skies and singing birds that swooped alongside him as the traffic parted. Castle had expected the journey to be quick, especially with the half skip that was carrying him, but he didn't account for the array of lamppost swirls and microphone newspaper moments that slowed his approach. When he reached the jewellery store he'd completed his rendition of Bruno Mars' I Wanna Marry You, several times. He prided himself on changing the lyrics, wishing he could call Kate so he could regale how clever he was before realising the flaw in that plan.

"Hey baby, I know I wanna marry you… Who cares baby, I know I'm gunna marry you".

He chuckled to himself again, as he opened the heavy door of the store. They had only just opened and the silence was permeated by the entrance of Castle, his lips still vibrated with his song and his feet tip tapped across the marbled floor.

"Good morning, Sir" the baritone carried across the small space. Castle grinned at him, like a lottery winner who had stumbled upon the Queen.

"Good morning indeed" he replied, in his best gentleman voice.

"And how can one help sir?"

"I'm getting married!" Castle couldn't contain the news any longer, pleased to have released the words he'd been fighting to keep in all night.

"Congratulations. Is it wedding bands you need?"

"Not yet. I need an engagement ring"

"Ah. Does the lady not wish to choose herself?"

"Well, see, she doesn't know we're getting married yet"

The store keeper raised an eyebrow at Castle who just waved a hand in the air.

"I see…"

"I haven't proposed yet" Castle explained with a sigh, annoyed by the man for not just knowing.

"And how do you know she'll say yes?" He challenged, a sparkle lighting the old man's eye.

Castle scoffed in response.

"She'll say yes. The universe told me. Plus, she can't live without me" he winked conspiratorially.

"I can't imagine why" the man murmured as he turned to the range of display cases. Castle had pushed the thought from his mind, he couldn't even begin to entertain the possibility of her saying no.

It took Castle thirty minutes of staring at rings, holding them up to the light and trying them on his own pinky finger before he thought he'd found the one. It was big, she'd pretend to hate that but secretly revel in it, what had caught his eye was the way it sparkled in the morning sun, the glint reminded him of the deep hues of Kate's eyes. He looked at it from all angles before holding it up to the shop keeper, who Castle had learned, was aptly named Alfred.

"Alfred, I think we have a winner" Castle held the ring up triumphantly.

"Indeed" Alfred had watched this same declaration several times now.

"There's only one way to be sure" Castle's boyish grin had now claimed his face. He handed the ring to Alfred.

"Propose to me"

Alfred spluttered, of all the things he was expecting, a proposal was not one of them.

"Excuse me?"

"Ask me to marry you!"

Alfred looked between the ring and Castle's excited face.

"Please? How else will I know if it's the ring?"

"I- but" Castle could imagine this was the first time he had ever stumbled.

"Come on, it won't mean anything, I won't tell anyone" he said in a stage whisper, rolling his eyes in true Beckett fashion.

Alfred glanced around before holding the ring before him.

"Will you marry me?". The words came out in a rushed whisper.

"Not like that! If you ask like that, of course she'll say no!" Castle grinned at him again.

"Sir, will you marry me?"

Castle eyed him again.

"It's not quite right… You need to be on one knee".

Alfred cursed him internally, the things he'd do for a sale.

"Sir, will you do me the honour of being my wife?"

Castle let out a squeal, a slightly more girly squeal than he cared to acknowledge. He fought the urge to flap his hands and pressed his lips together.

"It's the ring! It's perfect! She's going to marry me!"

Alfred fought to hide the smile fighting at the corners of his lips.

"Very well then sir".

Castle paid the astronomical sum and slid the ring box into his pocket. On the walk home he ran his fingers over his pocket, again and again, checking it was still there. This time, he didn't care who saw him, allowing his body to loosen into the jovial skip that had over taken his soul. He used the ride up in the elevator to calm his racing heart, his fingers brushing against his pocket one last time.

"Just say I doooooo. Tell me right now baby".

As the doors opened he forced his lips closed, he turned the key slowly in the lock and sneaked back in through the door. He tiptoed to their bedroom and could hear the soft sounds of her gentle breathing filling the air. Stashing the ring in his study he turned back to the bed, removing his clothes and sliding back in beside her. He pulled her long form to him, snuggling against her, bursting with the anticipation dancing within him. She opened a lazy eye, reaching forward to stroke his face.

"Babe?" She asked, her voice sounding like a dream. "I thought you'd gone". He snuggled into her, the golden strands of her hair tickling his face.

"Never" he whispered as he softly kissed her awake. All he had to do now was find the perfect moment to propose. He couldn't wait.