The Start of Us

Summary: Kate/Rick. What if Castle and Beckett had given into their feelings when they were in LA? How would their new romantic relationship change their working partnership? Can they make both work or are their attempts doomed to fail? Set during 'To Live & Die in LA'. Spoilers.

Warnings: Some mild sex in the first few chapters, followed by some angst later on.

First time writing Castle fic in a little while. I hope you like it and reviews are very welcome! :) VikkiHeat xxx

Chapter One

It seemed like only seconds ago that Katherine Beckett had been standing in her portion of the suite with her palm, slick with perspiration, grasping the ornate door handle. More than anything she wanted to open that door, both physically and emotionally. She had yet to tell Castle, but her on again; off again relationship with Josh had finally come to an end. After their last reconciliation, Kate knew that it was only a matter of time before she and the heart surgeon went their separate ways. It had hurt a little at the time, not because she had really loved him but because she was once again alone. Perhaps it was this, coupled with Mike Royce's death, which had pushed Kate to take this sudden and impulsive trip to Los Angeles. But was it also pushing her to take things a step further with Castle too? She couldn't be sure but she knew that, right now in this moment, she wanted nothing more than to be with him, closer than they had ever been before.

Kate was a detective first and foremost, and her gut instincts were telling her that Castle had feelings for her too. There was proof too, if he didn't care about her why would he have flown all the way to LA to help her on this crazy mission. For a while now she had been becoming sure that Castle following her around was having less and less to do with his research and writing process.

She inhaled deeply, letting the breath out slowly and finally opening the door. She stepped cautiously out into the living area of the hotel suite, rubbing her sweaty palms self consciously on the thighs of her pants.

Castle looked up when he heard her enter the room again, surprise showing in his bright blue eyes.

"Kate?" He questioned softly, beginning to push himself up off the couch.

"Don't talk." She replied, equally as softly, crossing the room to where he sat and settling onto his lap. She leaned in; breathing in the smell of his aftershave and the scent of him that was so familiar yet so exotic at the same time. In seemed to take an unbelievably long time for their lips to meet but it was worth it. It was everything their previous kiss had been and more, because this time it was real.

Castle meant to keep the kiss slow and sweet, wanting to savour every moment with her before she inevitably changed her mind. He wanted to believe that she wouldn't; that they would finally take their relationship all the way tonight, but he knew it was too much to hope for. Making Kate Beckett his own was too much to hope for. Kate's mouth was insistent over his though, and he found himself slipping his tongue passed her lips as he explored this unchartered territory.

"Kate," He breathed, unable to stop her name slipping out as his hands moved from her hips to tangle in her silky brunette locks.

She moved against him, her hips brushing against him and he had to stifle a moan. If Kate didn't stop this soon, he wasn't going to be able to control himself.

A smile teased as Kate's lips as she broke away from him to pull her shirt over her head. Castle was pretty sure he had stopped breathing as inches of her creamy flesh were exposed.

"Kate, are you sure?" He asked. Both of them seemed to know that this would be their last opportunity to turn back.

She nodded, leaning forward to unbutton his shirt. "I'm sure."

He kissed her again, sweeping her up into his arms and carrying her into his bedroom. He set her down on the soft sheets and they shed the rest of each other's closing. Their eyes locked as Castle moved over her, their body moulded together, and when he entered her, Kate sighed, almost in relief. This was what she had been waiting for.

Hours later, when Castle had fallen deeply asleep, Kate laid wide awake looking up at the ceiling. It had been amazing, better than she had imagined and she had daydreamt about this an awful lot. The way he had looked at her made her feel special; loved but it also scared her. What happened now? Could they go back to their normal, everyday life of solving crimes together? Was Rick Castle really the one woman kind of man? The fact that he had already been married twice worried her. What if she was just another in a long line of women who would sleep with Rick Castle and be tossed aside? Other women might have woken him up and demanded to know where they stood now, but Kate Beckett was not 'other women'.

Finally Kate slept for a few precious hours but woke as the sun began to rise over LA. She was still looking up at the ceiling but barely seeing it when Castle awoke.

"Could you not think so loud, you're making it very hard to sleep." Rick said, turning on his side and placing a kiss to her cheek; her throat; her shoulder.

In spite of herself, Kate shuddered at the touch of Rick's lips on her skin.

"Castle," She cautioned. "Rick." He cut her off with a kiss on her lips instead. It was slow and lingering, the way he had meant to kiss her the night before.

"Eww, morning breath!" She protested, pushing him away, laughing. She suddenly felt foolish for condemning him as something close to a womaniser. There had been so many opportunities where Castle could have taken advantage of their working relationship to get close to her, but until now he had always been a perfect gentleman towards her.

"Are you okay?" Rick asked, propping himself up on an elbow and looking across at her. "Last night was..."

"Unexpected." Kate finished. "But good."

"Just good." Castle pretended to look offended, focusing puppy dog eyes in her direction.

"More than good." Kate grinned, suddenly feeling both brave and reckless. She could get used to waking up to him, sleepy eyed with mussed hair in the bed next to her. "But perhaps you could remind me just how good."

Rick looked at her in surprise and awe. "This is what you want?"

Kate rolled her eyes, reaching for him under the covers. "This is what I want."