Title: Insights

Spoilers: Through Always

Summary: The everyday journey from friendship to a relationship. Post Always.

Disclaimer: I do not own Castle.

A/N: I was trying to think of a good idea for an angsty multi-part fic I could sink my imagination into over the summer, and after hours of brainstorming and a little bit of research, my fingers finally started typing and came up with... summer vacation fluff. Or quasi-fluff. Every relationship has its problems, after all. I'll add chapters as they come to me over the summer. Reviews are always appreciated.

Chapter 1: Scars

Her favorite flavor of ice cream is strawberry, but she will settle for rocky road. She is ticklish behind her knees but will deny it - vehemently. When she sleeps on her back, she sometimes snores, just a little bit. She never skips to the end of the book, no matter how curious she is about the identity of the killer.

Castle has learned so many things about Kate in the month since she arrived on his doorstep, wet from the rain and newly resigned from the NYPD. He now knows how she kisses and what she looks like bathed in the first morning's light the morning after. He learned how she tastes and the quickest ways to bring her pleasure. He also knew exactly where her tattoo was located, not to mention the story behind it. That had been a fun evening of sharing.

He found out the names of her grandparents and how old she was when she first broke her arm. He knows the name of the first boy she ever kissed, although she still refused to tell him about her first time.

He knows she still has secrets, parts of herself she keeps private even from him. And he knows not to push, that like any good writer, she will give him the important information as it becomes necessary, doling it out like rewards rather than in one giant, indigestible mass.

Not that he would mind knowing everything about Kate Beckett. Four years as partners had taught him a lot. One month as lovers had earned him more details and hidden parts. But every day he would find out something new, something unique and fascinating or ordinary and common. But never boring. Nothing about her was boring, not from the brand of conditioner she used to her political opinions to her taste in music.

She was a mystery, certainly, but a mystery with many layers. "So many layers to the Beckett onion. However will you peel them all?" she once asked him.

Back then, the question had presented a conundrum, but now he knew exactly how. Slowly. Carefully. And with exquisite enjoyment of the process.

Speaking of enjoyment, he was very much enjoying learning about how much skin Kate was willing to show in a bathing suit. Their first week at the Hamptons she wore a one-piece with a high neckline which left most of her back open and bare. Castle hid his disappointment in the suit hiding even more of her than the one she'd worn the time they went to Los Angeles. But the next week, he was rewarded with a return of that favored garment, the tan one with the little connector straps of fabric which hid very little of her toned stomach

By the third week, Castle was done with the whole one-piece bathing suit era. If Kate was uncomfortable showing off her body because of the scars – and he suspected that had a lot to do with it – she had no reason to be. Besides, his pool was private and the only ones that would see her were him, Alexis, and his mother.

So he bought her a bikini one day when they were out shopping. The purchase wasn't on a whim necessarily – he had spotted her looking at it for more than a few seconds. But then she had examined the space between the triangles of fabric on the top and frowned before putting it back on the rack.

Paying for it when she was in the dressing room trying on something else, Castle arranged for the swimsuit to be delivered to the house the next day. It would be a surprise, he rationalized, something she could wear if she wanted to wear it. No pressure.

However, when he had left it for her on the night stand in their room two days later, boxed up with a single red ribbon, he expected her to confront him about it. Having sent her up to change into a suit before their morning swim in the pool, he waited in the kitchen for her to come storming down the stairs and throw it in his face for presuming. Castle even had his arguments all mapped out, exactly what he would say to convince her how gorgeous she would look in the bikini, how much he wanted to see her in it.

Instead, she just did not come down.

For fifteen minutes he stood in the kitchen in his swim trunks, waiting. Fretting. Worrying a dent in his tiles as he paced back and forth, hating to take his eyes off the stairs for even a second but needing the movement. Why wasn't she coming down? Had he screwed up so royally buying her the bikini?

Then Alexis called him out onto the back patio where she was already dressed for the pool and sitting in the sun. His daughter needed sunscreen on her back, and finally, there was something useful for him to do while he waited for Kate. Of course, Alexis immediately inquired into his girlfriend's absence.

"Where's Kate?" she asked.

"She's, uh… changing."

As if he could fool the child he'd spent the last 18 years raising. "Then why do you look like you're in trouble?" she pursued.

"I don't know what you're talking about," he managed. Barely.

And then behind him he heard a noise - a clearing of the throat, deliberate, so as to gain attention. Turning quickly, Castle saw her standing in the doorway to the house.

In the bikini.

Looking absolutely stunning. Radiant, even.

Her skin had darkened into a light tan in the three weeks since they had left New York, and the color looked good. The color of the bikini – a dark purple with waves of silver – was also becoming on her. The cut of the suit was traditional, showing off a lot of skin, but it covered all the important parts adequately.

He did not even think to look for the scars until Alexis had bounded off towards Kate in excitement. "I love the new suit," the teenager gushed. "You look really good in it, too."

"Thanks, Alexis," Kate said, and he could see her fighting the embarrassment. Then she fixed her stare on him and – oh man – he wasn't sure if she was angry or happy, but she was definitely something very strong.

As his teenager jumped in the pool, the former detective stalked towards him with an unreadable expression, her hips swaying more than normal as she approached with slow, deliberate steps. Once she had reached him, sitting on the chaise lounge Alexis had vacated, she did not sit down. Instead, she simply leaned down so that her lips were a centimeter or two from his ear and whispered very softly.

"Next time, I get to pick your swimsuit."

He would have chuckled if her expression was not so serious, so saucy, and so sexy. Instead, he swallowed dryly as Kate picked up the tube of sunscreen Alexis had left on the seat and handed it to him. Then she saw down next to him but turned away, pulling her hair over one shoulder and presenting him with a great deal of skin on her back.

Time slowed down as his mind warred with his body over what to do in this circumstance. If Alexis were not just a few feet away in the pool, he felt certain that the purple bikini would be gone and he would be devouring Kate right there. But their teenage chaperone was an effective deterrent from such behavior.

"Castle?" she said a moment later, looking over at her shoulder at him expectantly. He stared at her blankly. Nodding to the sunscreen in his hand, she asked, "Can you do it or should I have Alexis get out of the pool?"

He looked down, and sure enough, that was what he was supposed to do – keep this fair skinned beauty from burning. And he could do that just by rubbing a slippery substance all over her body. Was this supposed to be a punishment?

"Work, work, work…" he muttered as he threw himself into the delightful task.

As he rubbed the sunscreen into her skin, he noticed Kate begin to lean back into him a little, perhaps unconsciously. Tilting his head to the side, he could also make out a sliver of her smile in profile. And her eyes were closed. She was enjoying the feel of his hands on her back.

Kneading her skin a little more deeply, Castle segued from a simple sunscreen application to a gentle massage, taking care to work the muscles of her shoulders and upper back. When he rubbed his fingers along the back of her neck, she let out a low moan, only loud enough for him to hear.

Castle added that to his secret list of things he had learned about Kate Beckett – she liked massages, especially around the tense area at the back of her neck.

"Do you like the swimsuit?" he inquired, speaking over her shoulder into one ear. His breath lifted a few stray hairs, and she either smiled widely at the way they tickled her face or at his question.

"I do like it," Kate answered without elaboration.

"Took you a while to come down."

He expected her to shrug or to give a dismissive response. But she just said, "Don't wear bikinis a lot, Castle."

"You should."

Then she shrugged, and he regretted bringing it up because she moved slightly away from him, ending the massage as she turned and reached for the tube of sunscreen. "I don't usually have access to a private pool."

So the scars did bother her, but it was something she could overcome in the presence of just him and his family. No one would judge her here or say anything rude or ask prying questions. They all knew exactly what the little circular mark between her breasts meant, what it signified.

"So you won't wear this to the beach later?" Castle found himself asking as she began applying sunscreen to her arms and legs. No, he wasn't asking. He was pushing her. He didn't want anything to hold her back, especially not this.

"Did you buy a private beach, Castle?" she returned, but the curve of her mouth turned it into a joke.

"What's the point of getting you a bikini if I can't show you off to all the other unlucky men out there?"

Oh, if Alexis weren't in the pool… if they were alone...

"Somehow I don't think you bought this swimsuit for other men," Kate responded with an arch of her eyebrow.

Her answer got to him. It was true. The last thing on earth he had considered when buying it was what other men would think about when they saw her in it. All he thought about was how he would feel at the sight of her, what the sight of her always did to him, whether she was in miniscule strips of fabric or a turtleneck and long pants. But he had another motive in buying the bikini besides indulging in one of his own personal fantasies regarding Kate Beckett.

"You're right, I didn't. I bought it for you."

Her gaze locked on his, and suddenly, she understood. That was the crux of it, really, the entire reason Castle had bought it. She wanted it – had stared at it in that store with more than a little longing – but she hadn't bought it. And more than just wanting her to have it, he wanted her to have the desire to put it on. He wanted her to know how beautiful she would look in it, did look in it.

"You look amazing, by the way," he pointed out. She blushed at the compliment and he tried to deflect the situation into something easier to deal with, adding, "I really like the color."

"Yeah, me too," she agreed readily, obviously glad to move on to a safer topic. "Purple is one of my favorite colors."

Favorite colors include: purple. Another layer of the Beckett onion peeled away.

The next thing he learned about Kate was exactly how loudly she could scream as he picked her up, unsuspecting, and threw her into the pool without ceremony. As she resurfaced next to a laughing Alexis, Kate wiped the water from her eyes before yelling and splashing at him in indignation. But she was not angry. Rather, she was smiling at him as though plotting her revenge. And Castle he realized something else about his new girlfriend, something he should have figured out long ago.

Deep down, despite protests to the contrary, Kate liked surprises.