I've been writing fanfiction for a loooong time. I jump from subject to subject, or more specifically relationship to relationship. When I was younger and in college, I wrote a lot more than I do now. Back then, this place didn't exist. Now I hardly ever write anything unless it's an attempt to eliminate the frustration and distraction of an unsatisfying end of some kind. If it gets so bad that I feel compelled to write, it's something I just need to get out of my system so that I could resume my regularly scheduled life.

It's the character relationships that sucker me back in. Castle has a lot of excellent characters, which is what's had me watching since the beginning. But with every show or game or movie or whatever I've written fanfiction for, there's always been this one blasted moment that sets my mind on fire and consumes me for days. Or weeks. Or months. And yes, sometimes even years.

For Castle, that moment lasted an hour. The writers named it "Knockdown".

I need to get over my Castle obsession quickly. I have way too many deadlines to meet to be so terminally distracted.

Chapter 1: The East Wall

The life of a cop is treacherous. They wear vests and carry radiation detectors and are constantly connected to a form of communication. They get yelled at, swung at, stabbed at and shot at. Even the good ones can find themselves in unexpectedly dangerous situations with unintentionally deadly results. Sometimes, it's the very drive to solve a case that drops the detectives working them. Kate Beckett is driven by her need to solve cases. And she's very, very good at solving cases.

Roy Montgomery had never seen a cop like her before. No, that wasn't true - He'd seen cops with her tenacity and drive, with an unwavering dedication to the cause of a partner's murder, or a son's kidnapping, or a sister's rape. In a world where terrible things happened to people every day, cops were not exempt, and they needed answers like everyone else.

What Montgomery had never seen before was a cop that survived their obsession. Obsessed cops got reckless, or careless, or stupid. Then they got dead.

He knew Beckett's record, had analyzed it hundreds of times. The truth was, he second-guessed himself about her all the time. It wasn't because he didn't believe in her – on the contrary, Beckett was the only detective he'd ever worked with that he felt he could truly believe in – but because every cop had their weak spot, and he knew he had to figure out what it was before she did. That moment of recognition, for her, would come a second before too late.

Beckett's weak spot should have been her mother's unsolved murder, and for the first few years it looked like it would be. She withdrew into the case, pursued it recklessly. It was her training officer that kept her alive, that kept her reasonably grounded. Somehow, Mike Royce had guided her to a balance few officers would ever strike between their own need for retribution and the dangers of their job.

He watched for the warning signs. He watched for triggers. He knew when to watch because he made it a habit to study his detectives. And over the last year, despite teetering a little when her mother's case reared its ugly unsolved head again, she'd managed to stay mostly grounded, guarded, and in control.

But there had been a time when that control cracked, where her guard dropped, and where the ground slipped out from under her, and though she had performed her job adequately the summer Richard Castle had gone off to the Hamptons with his ex-wife, her heart hadn't been in it. Her warmth as a person had gone to the Hamptons with Castle, leaving behind a cold, somewhat reckless shell of his best detective that only started to fill back in once Castle was back in the bullpen.

He was standing in his glassed-in office, staring out at the flurry of activity beyond the glass. Ryan and Esposito were both on the phone, tracking down the financials and phone records of their latest suspect. Beckett was parked in front of the murder board, filled to capacity with faces and post-its and facts surrounding George Landau's murder. She surreptitiously glanced at the elevators doors whenever they opened.

She was waiting on Castle.

He glanced back at the phone on his slightly cluttered desk, the one that delivered a phone call warning him of what a maid from a service had called into 911. The one that had told him Rick Castle had disappeared, leaving behind a wrecked loft and streaks of blood on the polished hardwood floors.

He knew what he was about to do would change everything, and he desperately wished that by holding the information back he could make the facts simply cease to exist, but he couldn't delay. Waiting would be deadly.

"Beckett," he called, his head just outside his door. "A word?"

The tall, beautiful woman took one last look at the board before walking purposefully forward. He let her into his office, shutting the door quietly behind her.

"What can I do for you, Captain?"

The summer had been hard to bear, not just because she'd shunned everyone in the precinct that cared about her, but because he cared for the well-being of those working under him, and she'd been in a kind of pain nobody wants to be in. They'd all watched Castle break her heart before he left and, though they knew he hadn't meant to, none of them had completely forgiven him for it. But when he came back, she slowly became herself again. After she broke up with the cardiac surgeon, she didn't seem to hurt the way she had when Castle was gone. Montgomery didn't make it a habit to keep up with his employee's personal lives, but that breakup, if anything, had allowed her to grow happier.

He watched her face as he gingerly broke the news to her. The woman had a masterful poker face, one he would have given good money for in his younger days, but it was nowhere to be seen. Her face crumbled, her eyes watered, and it was a very, very long moment before she could stand up and walk out to gather her team.

Kate Beckett had survived a lot of things that would get a normal cop killed, but something in Roy's gut was telling him this time was different. This time, she'd be facing something she'd never had to face before, and Kate Beckett was about to walk that thin tightrope every other obsessed cop he'd ever known had fallen from.

But he couldn't pull her from the case, either. She was Castle's best hope.

For now, he just had to pray she found Castle before she fell.

/chapter 1

Notes: This chapter pairs well with a lovely vintage of It's Not A Game by Harry Gregson-Williams.

I'm finishing about a chapter a day at the moment. I was going to write it all and then post it, but that would involve actually editing the thing. The plot bunnies are backing up, and I have work to do…so now that it's about half-written it's becoming a serial. I'll post one every day or so until it's either finished or I run out of pre-written chapters.

So far, this is the shortest chapter. I think it'll stay that way. The outline was 29 pages long in 12 chapters. I've fleshed out the first four chapters to 23 pages by themselves without a final once-over. If you enjoy longer stories, this one shouldn't disappoint.