I started watching Castle in re-runs and completely fell in love. I wasn't really planning on writing fanfic, but when I got the idea I thought I'd see how it went. This is my first Castle fic, so I hope it worked out and I'm reasonably in character. Post season-finale fic, with spoilers through the entire season.

Disclaimer: I own nothing

The Failure of Straight Lines

On a chess board the castle can only move in a straight line. And not even diagonally in a straight line. It can really only move in two directions, forwards or backwards, left or right, always along a predetermined path. A useful piece and a powerful one as well, but, like all chess pieces, limited in some way in the kind of movement it could undertake. Without cheating of course.

Richard Castle had found himself musing about chess more and more over the last couple of days. He'd learned how to play years ago, and he liked it. He'd even taught Alexis. Between the two of them there were a couple of pretty nice chess sets lying around the house. But they hadn't played in a while. He guessed they'd just moved on to other forms of entertainment. You had to admit, top of the line laser tag or fencing in the kitchen were both more fun.

But now that he'd suddenly acquired a lot of unwanted free time he found himself trying to find any way of distracting himself. Usually he tried to lose himself in his writing, but right now that had about as much appeal as going to speak at one of his mother's many events to recruit new clients to life-coach. Instead he was reduced to contemplating chess pieces.

He was a lot like the castle, he reasoned, and more than just in name. He liked to move from point A to point B as quickly as possible. If he wanted something, he analyzed the situation and figured out the best way to get it. And everyone knew that the shortest distance between two points was a straight line. He'd been doing it all his life. How to get through school? Figure out the minimum amount of work that needed to be done, and then do it. How to become a successful writer? Come up with interesting plot, write novel, get the book published, develop the public persona to go with it. Of course the details had been more complicated than that, but the basic point still stood. He'd figured out what needed to be done and he'd done it.

And he'd found the straight line approach worked in most areas of his life. To make his daughter feel better: he figured out what was wrong and he fixed it. Either by talking her out of her mood, or, if it was more serious, he just found out the details and removed the roadblocks as quickly as possible. No one hurt his baby girl. Dealing with his mother was just as easy, it involved a combination of flattery and threats, well, that and making sure she didn't go too long unsupervised and that anything dangerous was well out of the way. Some people baby-proofed their houses. His apartment was Martha-proofed. It had been the same with Meredith, indulge her every whim, flatter and cajole, feed her ego and he got what he wanted.

And that pattern tended to hold with most women, at least it was with the women he met. If he met one he was interested in, he went for it. It was usually fairly simple, after all he was the famous Rick Castle. It just required a bit of flattery, a bit of charm, sometimes a glamourous outing, some suggestive comments and by the end of the evening he was usually being invited into her apartment. Again, the details were always different, but the system generally worked. Most of the women he met were just looking for a good time, and he fit the bill.

He'd been using the straight line approach for as long as he could remember, identify then solve. Figure it out logically. It was how he wrote his books. He plotted the murder then worked backwards to figure out what the killer would have needed. Sure there were twists and turns, but the usually resulted from his protagonist not having all the facts, and picking up the details out of order as he moved through the story. But the motivations of the murderer always followed a series of straight lines. Because no matter how complicated people thought they were, everyone followed rules.

When he met Detective Katherine Beckett he'd thought he'd never met anyone who'd followed straight lines as much as she did. From the cut of her suit, ever-so professional, to the way she solved a crime. First she went to the crime scene, got any preliminary results from Dr. Parish, checked with Ryan and Esposito for background information, notified/interviewed the family, looked for motive, established a timeline, then re-interviewed any likely suspects once she had something to go on. Lather, rinse, repeat until the case was solved and whoever had committed the crime was in her custody. She had a system. An effective system to be sure, but a system none the less.

While he watched her system help solve their first case together he'd been intrigued by the beautiful woman. So he'd decided to implement his own system. Flirt, charm, flatter, make suggestive comments. He'd done it all before, and he'd done it to great success (though perhaps not as often as she assumed). But Kate Becket hadn't reacted as expected. It had looked promising to begin with. She'd leaned in to whisper in his ear. But then she'd walked away from him, without looking back.

And standing there watching her go, he'd realized something; beneath the straight-cut suit jacket Katherine Beckett had curves.

In that moment he knew he wanted her. Both literally and literarily. Wanted her as his new protagonist, wanted to get to know her, wanted to figure her out. And that meant spending more time with her. So, as usual, he'd determined the quickest way of getting what he wanted. The fact that the mayor was a fan meant that weaseling into her world would take at most a day, maybe two.

With that he became Detective Beckett's shadow. And he learned the details of the straight lines she followed on the job. Gather as much information about the victim and the suspect as possible, then interrogate. Don't just rush in and make accusations. Reveal nothing, but don't take any crap from anybody. Get all the facts, and then go catch the bad guy.

But it became abundantly clear that that was not all there was to Kate Beckett. The next curve she threw him was the degree of empathy she was capable of. The feeling she showed towards a broken young woman had floored him. He'd assumed it had been an act, a way of building a rapport, building trust, in order to get what she wanted. But that wasn't the case. She always empathized with the victims, even when it made her life harder than it needed to be. Because although it drove her to catch the killer, it also made her too involved, less objective. The empathy could distract her from the quickest, straightest path.

And after he'd found that first curve, that first inconsistency he'd wanted to find them all. So he did what he always did, he badgered, and cajoled, surmised and just generally irritated her until she told him what he wanted. And his methods, as always, were effective. He'd guessed personal tragedy, but missed the mark on the details. When she told him about her mother he felt like he'd been given a precious gift. It didn't mean she encouraged him, but at least she trusted him a little. A fact that was further proven when she showed up at his apartment, stuck on a case, needing to find closure, looking for his help, something he'd been only too willing to give.

After that he'd figured his plan was working so he kept going, slowly getting closer. He used all his usual tricks to win her, flattery and charm, teasing her until he she couldn't ignore him anymore. She didn't ignore him, but she also didn't succumb. And she gave as good as she got. The red-headed detective saw right through his tricks, didn't fall for the persona or the celebrity. And somewhere along the way it became more than just figuring out his muse, and finagling a way into her bed. He wanted to see her smile, wanted her to be happy, wanted to give her something. Something that was just hers, something beyond an espresso machine she'd pretended to disapprove of.

Clearly the best gift he could give her was to try and solve the biggest problem in her life. So he decided to look into her mother's case. After all, someone might have missed something. It was possible. And he had connections he could use to see if anything could be done. It had seemed like a simple equation to him at the time, solve her mother's murder, give her closure, win her trust, and her affection. If her undying love came with it who was he to argue?

Of course, it wasn't going to be a fast plan by any means. So in the meantime he took her to an exclusive charity event. He even surprised her with a dress. A beautiful dress. And even though she'd appreciated it, she'd been uncomfortable. The woman could run after a suspect down a fire escape wielding a gun, but dressed up to go out she'd been self-conscious. Like most of the women he brought to events like this she'd been dazzled on the red carpet, but unlike the others she'd never been completely at ease once inside, more comfortable snarking with her colleagues then chatting with the other guests. Most women would have been completely charmed, but she hadn't even really enjoyed herself until his mother started in on the public humiliation. Humiliation, he should point out, that Beckett had refused to save him from, no matter how much he pleaded. And despite the fact that the evening had been successful, in that they'd made an arrest, he'd be lying if he said that's all he'd been hoping for.

Still, he did get her in his apartment for breakfast the next morning. And even though it wasn't because she'd spent the night, as he watched her giggling with his mother and his daughter over eggs it really seemed almost as good. Almost.

So he'd stepped up his game. She didn't like big formal events. Fine. He'd invite her and her colleagues to his apartment to play poker. It was perfect. It was informal, and would give both of them a legitimate excuse to bait the other, something they both clearly enjoyed, though she'd die before ever admitting it. And as he watched her across the table, smirking at him and having a good time, he decided to ensure the evening ended on a high note for her. He let her walk away the big winner. After all, in his experience women liked to win. He'd learned that losing on purpose put them in a better mood, even if they caught on. Both Meredith and Gina had been easier to live with if they got what they wanted. Besides, he'd wanted Kate to feel good in front of her friends. She deserved it.

But again, despite his planning, she hadn't reacted like he'd expected. When she found out he'd thrown the game she'd been insulted, tried to pay him back. Didn't want to be flattered and indulged like most of the women of his acquaintance. She'd wanted him to treat her like an equal. Couldn't look the other way when he told her little white lies to make her life easier, even if the results were less pleasant for herself. The end never justified the means with his Kate. And it threw him through a loop.

As he'd been recovering from her latest turn her hulk of an ex-boyfriend had shown up. Someone who was effectively the male version of his lovely detective, minus the empathy and the sense of humour. And not nearly as beautiful. And he had to admit he'd felt threatened. How could a man like that possibly appreciate her? Sure he probably appreciated her professional abilities, but how about her sense of humour? How about the fact that she read plays. How about her loyalty to people she cared about. Besides, the idiot had left her once already. Any man stupid enough to leave Kate Beckett didn't deserve a second chance.

Castle decided he needed to do something that would leave his rival in the dust. So he sped up his plan to solve her mother's murder. It was perfect; he'd solve the biggest mystery of her life, she'd be grateful, realize how much he cared, and the Cro-Magnon from the FBI would be completely forgotten. He'd been so sure that's how she'd see it. He should have known better by now that Kate Beckett never conformed to expectations. When he first broached the subject she told him in no uncertain terms that if he opened that can of worms he was out of her life.

But it was too late. He'd already opened the can of worms. And since he had, he couldn't not tell her. Especially since what he'd found inside could be important. Much as it pained him to admit it, his mother was right; he had to tell her, even if he lost her. Which was pretty much exactly what had happened. She'd shut down. Barely heard what he'd said, brushed off his apologies, and his promises to do anything she wanted, to do whatever it took to see this through, and left him standing in the hall alone. But not before telling him that if he showed up at the precinct the next day, or any day after that, she'd shoot him between the eyes without hesitation.

So now he had a problem to solve. And he knew the straightest way to solve it would be to show up at her apartment, and bang on her door until she let him in. Then either grovel or cajole until he was forgiven. But he was finally learning that as by-the-book as she seemed on the surface, Kate Beckett was really one complex loop after another. And he was finally going to try to work with that, even if it meant that at the moment he felt like he was Alice Through the Looking Glass, finding that walking in the opposite direction tended to take you where you wanted to go.

She'd left him in the hall two days ago. They'd been the longest two days of his life, and explained why he was currently searching for any possible distraction in his apartment. But at least he hadn't gone to her apartment. He wasn't going to pressure her. He was going to give her space. And he was going to come up with another type of plan to gain her forgiveness. And whatever it was, it wouldn't be straight. Because, off the job, in her private life, Kate Beckett didn't do straight. So although Castles typically moved in straight lines, he was going to learn to do figure eights if necessary.

Because although the shortest distance between two points might be a straight line, if the straight line never got to your intended destination, then it stood to reason that another path, even if it was almost circular was the way to go. And if running in circles was what it took to achieve Detective Beckett's forgiveness, then he didn't care if dizziness became a permanent condition.

Besides, he could always just keep a pack of gravol in his pocket.