A/N: Wrote this before I saw sneak peek 4, so it's AU of whatever promotional stuff you've seen for Setup, which it is set in. Hope you like it! (: I haven't seen the first ten minutes that are online, but I have seen the sneak peeks, and it needs to be 10:00! So this is what I do in the meantime. ;)

Disclaimer: I...still don't own Castle.

Castle sat on the small portable bench in the white tent which had been set up in seconds. He rubbed his hand over his face tiredly, flashing through everything that had happened in the past hour. He glanced at his watch, doing a double-take. Had it really only been an hour...?

They'd caught a case yesterday, a robbery-homicide. They'd gone to find what had been stolen, having found an address in the vic's apartment. It had been a huge warehouse with storage units with yellow doors. Castle had had a bad feeling about it, but Beckett, being Beckett, had insisted on following the lead to wherever it led. He'd stayed outside of the door they'd been led to. He should've gone in with her, should've been there with her. He'd heard her gasp, saw her sprint out of the storage unit, a look of terror on her face. She screamed at him to get out, and he started running as she slammed the door shut and followed him. She whipped out her phone, yelling into it, but Castle couldn't tell what she was saying. He was too busy trying to figure what was going on, what could have been in that room that had terrified the ever fearless Kate Beckett. They'd gotten out and she'd started pacing, waiting for whoever she'd called.

"What's wrong?" he'd asked quietly against the building.

"Radiation," she'd replied, breathing hard. "There's radioactive material in there, and it's dangerous, and if Homeland Security doesn't get here soon, all of New York could be exposed to it. Whatever happened to our vic, this was not a typical robbery gone wrong. Something huge is going on here." She continued to walk back and forth in front of his feet.

"Wait, so you were exposed?"

"Yes, Castle, I just said-" she frowned and paused her movement as he stood. "What?"

He reached out suddenly and hugged her, burying his face in her hair, but as soon as she realized what was happening she pushed him off, backing away from him.

"Castle, what are you doing?" she snapped.

"You just seemed so alone," he said simply, as if it were obvious. "Now I'm in the same boat as you."

She gaped at him. Castle had just willingly exposed himself to radiation so she wouldn't feel "alone". She watched as he sat down casually and started messing with his phone. She shook her head, speechless, and sat beside her, glancing over his shoulder at the screen. He was updating his Twitter, of all things.

"Homeland Security's going to take that," she reminded him gently. "They'll say it's contaminated."

"I can always have CSU pull the card for me and get a new one," he shrugged.

"They better give me these clothes back," she commented. He realized she was just talking to fill the silence. "I like them. Especially the boots." She examined her four-inch heels as if thinking of all the ways to kill someone with them, while he switched his focus to Facebook. "Thanks," he said finally.

"Anything," he replied.

Two black vans with tinted windows screeched around the corner, skidding to a stop in front of them. A team of people jumped out of the back, covered head to toe in orange radiation suits. They swarmed on the building, grabbing them by the arms and pulling them to their feet, practically carrying them away.

They were separated, and Castle lunged out to grab her hand but missed. The orange suits stepped between, and Castle shouted, "Beckett! BECKETT!"

He heard her yell back at him, but he wasn't sure if it was panicky or reassuring.

"Kate!" he screamed, before they dragged him into the white tent which had been erected in seconds.

They'd told him to stay in the white room and he'd been left alone for the better part of an hour, during which he'd done nothing but worry about Beckett. How had it been an hour? He felt like he hadn't seen her in days. In a brief moment of madness he wondered if the government had the ability to stop time. He shook his head. "They can't stop time," he muttered to himself.

"Hello, Mr. Castle." Castle jerked his head up to look towards the flap in the tent where a man in an orange suit stood. Castle jumped to his feet.

"Who are you?" he asked.

"I am a member of Homeland Security, my name is Agent Tallon. Before we take you back to the department, I wanted to ask you some questions, get your take on what happened. My primary concern is for the people."

"And is Detective Beckett part of 'the people'?" Castle asked. "Where is she?"

"We already talked to her, she's heading back to base now. She wanted to stay and wait for you, but we decided it would be better for her to go. It took some persuading, though. You must be really special for her to get that mad."

"What'd she do?" Castle asked nervously.

"She sat down, crossed her arms, glared at my agents, and refused to move," the masked agent told him. "She started yelling at us when we tried to pull her up."

"Why couldn't you just let her stay?" Castle's mind raced. She had been that adamant about waiting for him?

"Because she's been exposed. If you don't get decontaminated it'll seep into your pores and then you get cancer and then you die."

"Well that's a little harsh," Castle muttered in alarm.

"That's the truth, Mr. Castle, I'm not paid to sugarcoat things, I'm sure you get enough of that working with the police." Castle opened his mouth indignantly, but Agent Tallon cut him off. "Now I need you to tell me what happened. Were you exposed?"

Castle stared straight at him defiantly. "Yes."

The guy paused. "Really? Because the detective said that you didn't go into the storage unit with her."

"No I didn't," Castle said, folding his arms. "But I hugged her afterwards."

"After you left?"

"After she told me she'd been exposed. She said she'd encountered radioactive materials so I hugged her."

The agent attempted to drop his head into his hand but failed due to his mask. "If you don't mind me saying, Mr. Castle, you are an idiot."

Had Beckett been there, Castle thought, she probably would've said something along the lines of, "He signed up to shadow a homicide detective. No kidding." But Castle just shrugged.

"Then we can take you back to base, have you decontaminated, and then we can talk." He hauled Castle to his feet and led him out of the tent.

An hour and a half later, he'd been scrubbed free of all radioactivity—and the top layer of my skin, Castle complained to himself, examining the backs of his hands, which were pink. They'd given him some clothes and directed him to where he was wanted. When he entered he was once again in a plain white room. The carpet was rough on his barefeet; apparently shoes didn't come with the rip-off-your-epidermis deal.

The only piece of furniture was a small bench, on which sat his partner, wearing sweatpants and a black t-shirt. She had a carton of McDonald's fries on her lap and a coffee in her left hand. When he walked in, she looked up. "Hey."

"Hey," he said, nodding. Looking at her face, he could tell that her skin was reddish as well.

"You look like a lobster."

He instinctively pressed his hand to his cheek. There hadn't been a mirror in the bathroom he'd gotten dressed in, and he'd been wondering how his face had fared.

"It'll go back to normal in a while," she reassured him as he sat beside her. When she turned to look at him, her wet hair flicked droplets onto his shoulder. "Hungry?" She offered the fries to him.

"Starving, thanks." He hadn't realized how hungry he'd been until he'd smelled the greasy food. Of course, he hadn't realized how worried he'd been until he'd seen her either.

"I hear Homeland Security believes you're a threat to your own safety," she said casually.

He glanced at her, checking to see whether she was joking or not. Her face was serious as she picked through the food, but he could tell that she was. "Yeah, well, I hear that you scared off a bunch of government agents."

Neither was necessarily true, but they accepted the accusations. "So what's going on? Do you have any clue? Because all I know is that I found a bunch of cobalt in the middle of New York City."

"They haven't told me a thing," Castle replied. "I was worried about you."

"Why? It was just radiation. It won't kill me." She considered what she'd just said. "Well, it won't kill me instantly."

"You never know," he shrugged. "I didn't know how much you'd gotten."

"Trust me," she grinned. "I'll be around for you to annoy for a long time. Are you trying to get me to die so you can put it in your book?"

He glared at her. "That's not funny. At all."

"Okay, okay. You'd think that the guy who writes about death for a living would appreciate a little gallows humor."

He bristled. "You'd think the girl whose mother was murdered would take it a little more seriously." She sobered, and he realized that he may have taken it too far. He dropped his voice. "Normally, I love gallows humor. You know I'm the first one to say what's on everyone's minds when a body drops. But not when it comes to you."

Between sharing the food and arguing, they'd come very close to each other. At that moment they both noticed. They could've turned away, like they did so often, but they were alone in a Homeland Security holding room, having just discovered a radioactive bomb. Both of them were vulnerable and scared, and instead they closed the distance and she kissed him gently. She pulled away slowly and stared into his blue eyes for a moment. They were caught, transfixed, until someone cleared his throat. They jumped and looked towards the door so fast they got whiplash.

The agent looked back and forth between the two of them in amusement. "Are you two sleeping together?"

At the same time, they said, "No."

He raised an eyebrow, smirking slightly. "Uh-huh." He crossed the room to where they sat, standing in front of them and putting his hands in his pockets. In a moment he'd composed himself into a stern expression, all business. They were forced to look up at him as he began to talk.

"You're both clean and free to go," he said. "We'll be taking over for the police. You can continue doing what you're doing. We deal with threats everyday. It'll be over and no one will ever know."

Beckett stood suddenly. "No. I'm helping you. This is my case."

"You're not needed anymore. Go back to your job."

She glared at him. "This is my job."

Castle watched her argue her case, fire in her glare. She hadn't admitted anything, but that kiss had been enough admission he'd needed. And maybe she wouldn't open up to him just yet; Agent Tallon's interruption had seen to that. But he could live without hearing it.

Maybe some other day.

A/N: Hope you liked! Please don't spoil anything, some people like to be surprised!