A/N: I know I have quite a few stories going on right now, I've had this sitting on my laptop for a while now, and since it is almost already finished, it'll give me time to finish everything else while I release this one…

It is a crossover between Castle and Grey's Anatomy but since it is mostly Castle related, I am not putting it in the crossover section, I hope you guys are okay with that. It is set somewhere in Castle season 4, so spoilery up until Killshot, and at the beginning of GA's season 7.

DISCLAIMER: I do not own anyone or anything even remotely related to Castle, Grey's Anatomy or their creators, Andrew W. Marlowe and Shonda Rhimes. I am just having fun with them.

"I don't see anything," Seattle police officer Brian Smith commented after a several seconds of silence. He shot a nervous look around the room and at the numerous doors on the left side, having no idea if they should go in or not. "What do you think?"

NYPD Detective Kate Beckett stared at the tall, blonde police officer before nodding as she tightened her hold on her gun. "Let's keep on this side of the door until we're sure we're not walking into a trap." She had a bad feeling about this, but she wasn't about to admit it. The police officers present in the hallway were nervous enough as it was, and Castle would try to make her leave the premises. She couldn't leave, not yet.

They had been in Seattle for three days now, and the case they had been working on was about to be wrapped up, as soon as they'd captured their suspect.

The victim, Manuela Donovan, 19 years-old, had been found drowned in her own pool a few days prior and it wouldn't have brought forward much attention to the press and media if she hadn't been Terrence Donovan's daughter, the governor of the Washington state.

Beckett had been surprised when Captain Victoria Gates called her in her office five days ago to inform her that she had been specifically requested to work on a case on the West Coast.

The Seattle's Police Force weren't getting anywhere after a week so Donovan, getting restless over his daughter's unsolved murder, had send Manuela's complete file to the 12th Precinct and requested New York's best, detective Katherine Beckett on the case.

Beckett's reputation was proven less than twenty-four hours later when she had called governor Donovan to confirm his daughter's murder, and that she had a potential lead. Relieved to have made the right decision, the governor immediately flew her and Castle over to Seattle to solve the case.

Neither Beckett nor Castle had a break from the moment they had set a foot on the West Coast, running from interrogating suspects to spend several hours at the victim's house before going back to their hotel to run theories along with Esposito and Ryan via webcam. They had been teamed up with detective Brian Smith and several other officers and, while they were good at their job, Castle had to agree with Donovan. They were no Beckett.

They had finally managed to trace back their prime suspect the night before but when they went to his place to arrest him, he had vanished. Several hours later they got a call from the Seattle Police Department advising them of an officer having spotted the suspect and, three hours later brought them to Stewart Jensen. The 23 yr-old man was one of Manuela's classmates in Seattle U and his alibi came crashing down the day before, confirming his presence at the crime scene at the time of Manuela's death and, as it turned out, two other similar crime scenes.

Unfortunately for him and lucky for them, Jensen managed to run away from Beckett and the Seattle cops but he only made a couple of blocks before rushing into a building in construction. He was still nowhere to be seen but with about fifteen cops inside and out the place, it was only a matter of time before they put their hands on him.

"Where do you think he went? We're blocking the only way out, unless you count the stairs, but they're a dead end. Maybe he plans to jump through those windows..." Castle pondered absently as he looked around as well for any likely possible scenarios. They were at one end of the hallway on the third floor of the building and it was hell to search for anyone in this place because of all the construction material and plastic drapes everywhere.

"Or maybe he's-"

"Shhh." Beckett put her hand over his mouth to shut him up and Castle fought with all his might to keep himself from pressing his lips on her soft hand. Things had gotten better between the partners lately but, if he knew Kate was getting there, she still needed some time before finally being able to commit into a relationship with him. "whht?"

Kate used her gun to point somewhere to the left about thirty feet away. She signalled for Smith and two other officers to back her up while she slowly made her way to the elevator shaft, having noticed the plastic drape covering it move. She got the feeling that if she had seen him it also meant he could see them coming, but it wasn't as if they had a choice. They had to catch him.

Kate couldn't help but think that it had been a very good thing for her to decide to wear flats that day, since heels would have been a dead giveaway every time she would have made a step in any direction.

The detective was quiet, everybody was or at least until someone slipped over a piece of plastic and fell down. The distraction was all Jensen needed and he jumped out of his hiding place the moment everyone turned around, but Kate saw him run away from the corner of her eye. "Stop! Police!"

She took after him knowing Castle was right behind her and, judging by the loud rumble behind her, at least four or five other cops as well. "Jensen! Stop or I'll shoot!"

The man glanced over his shoulder but didn't stop. Kate was catching up to him but if she wasn't fast enough, chances were he'd be able to reach the stairs before she did and used them to disappear onto the lower floor. "Jensen, last warning! Stop running now!"

Kate didn't know what made him stop. Maybe it was the small piece of 2x4 that lay across the floor that made him stumble.

Maybe it was that she had finally raced up to him and managed to grab his arm to hold him back.

Maybe it was that he tripped over his own feet and crashed over the temporary rail protecting the construction crew from falling down the massive glass floor in the center of the new room they had just entered, floor that had been a gaping hole just a few hours before.

For a second Kate was startled when she heard Castle scream her name, but it was already too late when she snapped back to reality. Her wrist was caught in Jensen's powerful hand as he crashed right through the glass, dragging her with him.