Title: Number 47
Summary: Inspired by a tumblr prompt. Beckett disappeared a year ago, and since then Castle has worked with Ryan and Esposito hoping that one day they'd find her, or who took her. What Castle didn't expect was to find her behind behind locked door number 47 during an undercover mission.

Full prompt: Pre caskett AU. During a take down, Beckett is abducted from the scene. Nearly a year goes by with no leads of where she disappeared to, the boys including Castle who never left the team because of his search for the woman he loves, go undercover to try to catch a powerful man who is trafficking women and children all over the world. When they open the door to one of the captive's closed off rooms, they're met face to face with their missing leader, Number 47, Katherine Beckett.

The air was crackling with tension as he walked down the long corridor lined with metallic doors and heavy locks. The man who was walking ahead of him was a massive frame even to Castle, clothed in a non-descript denim jacket and jeans, and as he'd opened the door to the corridor he had explained that this was just a dock. Merchandise was unloaded and reloaded here, few stayed longer than a month.

"We're loading number 18, 47, and 53 today," the man mumbled as they passed a guard dressed in khakis and a black t-shirt holding a weapon in two hands that seemed to be more fitting in Afghanistan than in an off-grid dock. "Taking them up north and then to the buyer… have you handled merchandise before?" The man stopped and looked at him with narrowed eyes.

"No, not this kind of merchandise," Castle admitted, and did his best not to swallow against the fear that had built up inside of him. For a moment Alexis' face had flashed before his eyes. Before he had left for this mission she had pleaded with him to stay, reasoning that he was not a cop and if he went missing like Beckett did then she might end up just like Jim Beckett. That was when Castle had cradled his daughter's head in his hand, but had not been able to get himself to stay. Until he had brought the people who'd taken Beckett to justice he would not be able to rest.

"Number 18 and 53 are easy goods, won't put up a fuss, but 47 is a dynamite… don't know when she'll explode." The man glanced over at the gun which the guard was holding, as if he was recalling a memory, treating it like a sweet candy that he sucked on for a while, before he grinned up at Castle. "It's been fun, but impossible to sell, been here a long time."

"Fun?" Castle didn't want to ask, but he could not stop himself. Even without asking his imagination was already running wild. This could be Alexis in one of these cages they'd created, handled like inanimate cargo, a product not a human being. He steeled himself against the disgust he felt.

"Alex, are you asking for a free sample?" The man and the guard both chuckled. Alex was his assumed name here.

"What, no!" He'd never thought he would need to prove himself loyal like that. So far his fraudulent criminal record that had been conjured up with the help of mob connections and deals made with criminals over the past 6 months had been mostly enough. There had been a few tests, but little which went too far over the line which he had drawn for what was right, or what was wrong.

The two men cracked up laughing, their mouths open wide as the cackling laughter bounced eerily off of the metal doors and echoed through the corridor that except for them was completely empty.

After the men had calmed down and given Castle a slap on the back, the man and Castle continued towards a door marked with the number 18 on it. With practiced ease the man entered the room and cuffed the young girl's hands together – Castle didn't want to meet her face because he knew he would be haunted by her for the rest of his life. Today he was gathering intel, and they would not bust this place up for another few days, not until they found the leader of the organization, or at least the branch that was operating on the northern part of the west coast.

The girl didn't say anything, and Castle barely heard her breathe as they chained her up on the floor in a container. She had long black hair, and her pink sun dress was torn and dirty, and all Castle could think was that it had been two months since it had been warm enough to wear something as thin as that. A quick inspection revealed little bruises on her pale skin, only a few on her knees and a yellowing bruise on the inside of her ankle. Had there been more before that now had faded? He didn't want to know.

47 was up next. As they walked into the building again the man started to talk, telling stories of number 47 and the time she had spent in the dock.

"47 came here nearly a year ago, and she beat up quite a few people, the dumb chick even tried to escape once." He turned towards Castle and pointed at a scar below his lower lip. "She tried to bite my face off once." The man must've recognized the look of horror on Castle's face and misinterpreted it as fear, because he continued. "She's like a puppy now… I guess it took a while for it all to sink in for her, I don't think she's that bright."

Inside the corridor again Castle wished that he hadn't taken this on, and that Esposito and Ryan should've been here instead, or someone out of major crimes. Despite the fact that he could've been recognized it hadn't taken long for the NYPD to see that Castle fit the description of the workers inside the organization; white middle aged male with a large disposable income, and a grand persona. The pitch Castle had given had helped some as well – it was that pitch he now regretted when knowing he would be faced with another girl that he would not be able to get out. It was too late for these three girls.

Walking the line of moral ambiguity was easier in theory.

As the door to 47 was opened, and unlike the rustle of fabric that had sounded when 18 was unlocked as the girl had scrambled into a corner, they were met only with silence. The heavy boots of the man echoed as they hit the floor more forcefully than before, establishing a clear dominance from the get-go.

"With chicks like these you can't hesitate for a moment," the man had said before opening. "You have to show who owns them."

The woman was so clearly not a girl, but the way she was pressed up against the wall on the thin mattress didn't give much air of anything but fragility. Whatever had been of her before, whatever fighting spirit that had been in her which warranted the war stories was gone. Before him was not a woman who would bite a man's face of. This was a woman who would stare down the barrel of a gun and say 'please', begging you to pull the trigger.

It was possibly for that imagery that he forgot to avert his eyes from her face, his momentary slip of character that made him look at her. It was her.

Halted mid-step he stared at her face. The cheekbones and strong jaw, the round hazel eyes, and those lips. It was her. He wanted to drop the act and leap forward and grab her in his arms, pull his gun from the waistline of his jeans and put a bullet in the man's scull.

But he couldn't.

Revealing who he was, who she was, and the whole operation would kill them all. It would warn the people running the organization, and all the girls in the facility would be dead or gone before any team managed to get here in time. He would end the world for her, but not like this.

For a moment he held his breath, waiting for her to recognize him, but unfocused eyes danced over him unseeing. There wasn't even a hint of recognition behind her eyes telling him that she knew him. Had she forgotten? Had they hurt her so that she would never know again?

His stomach threatened to turn.

He needed her inside the cargo, and far enough from the building to keep her out of harms way. As they walked out with her towards the cargo with her chains clinking and her feet scraping over the ground in a way she would've never done the year before, he couldn't help but think of when he saw her last.

They'd been out looking for a suspect when they had split up inside a building. She had been reluctant to split up, but he had argued that inside the labyrinth that was inside the best chance of catching the suspect was to split up He regretted those words, and each time he reminisced of the way her eyes were widened with worry, determination, and suspense as she handed him her back-up piece he would be hit with a gut wrenching nausea. The last part of her he'd seen before she turned the corner completely had been a ponytail. Her hair was longer now.

After chaining her up next to the other girl Castle had excused himself, saying he needed to smoke. He wandered off to the far side of the property, picking up his phone and dialing a number he knew he shouldn't be dialing yet.

"Castle? What's happening, why are you calling?" Esposito asked, his voice urgent.

"You have to go in now." Speaking proved harder than he thought. Beckett was inside that container that was about to be shipped off to god knows where, to god knows who, and it would be nearly impossible to trace it. This was their chance. Their only chance. He was selfish, he knew that. But this was Beckett.

"Do you have the information?" The harshness in Esposito's tone spoke of the trials they had gone though in the last year, and the tests their friendship had not passed.

"They have Beckett," he said with a rush of relief which was replaced with worry of all the things he could, and could not, do.

"What?" To all of them Beckett was dead, until now.

"She's in the cargo, and they're going to ship it off in a few hours… this is our only chance!"

"Are you sure it's her?" All of them, even Esposito, had had many times where they'd sworn they'd seen her on the streets. They were well versed in the disappointment of realizing it was not her. Every female body that turned up they steeled themselves against that it could be her.

"One hundred percent."

"Shit."

"Yeah."

"I'll talk to Martinez." Esposito hung up, and Castle took the time to light up a cigarette and placing it between his lips. As he breathed out the smoke in an uneven breath he prayed that Martinez would find a way that they could save Beckett. He couldn't leave her alone again.

He needed to save her this time.

A/N: Going to try to get the 2nd and final part uploaded tomorrow. Reviews are very much appreciated!