Disclaimer: Still don't own Chuck, but honestly, at this point, we've (me, MXPW, Liam2, ne71, crystal elements, and Mikki13) created a universe that's not really Chuck anymore, haha.

A/N: Okay, so this story is a follow up to the original Adorable Psycho oneshot. This is a day after the events of that story, and it begins to explore the history of Sarah in this universe, and why she is what she is. You get no definitive answers here, but you start to get clued into who she really is, and what her issues really are. A big, whopping thanks go out to MXPW for his help with this story. I admit, it was a trainwreck before he saw it, and told me point blank that it sucked and needed to be completely rewritten. He was absolutely right, and the story is now much better for it. Hopefully you'll agree, and you'll let me know. Thanks!

Adorable Psycho' Debriefing

Paper work sucks. Not that this was news to Colonel John Casey. Hell, for too many years, he'd been filing reports the day after sanctioned kills. But this time, it wasn't his doing, and he damn sure didn't want to be the one to clean up the mess. But then, Walker, when her head was on straight at least, was a damn fine partner, and he didn't want to see her get swept up in a shit storm by the system, so he'd spent his morning in Castle trying to find a way to get the bosses to see things from his point of view.

Not that it was an easy task. Hell, Walker had gone way out of bounds the previous day, killing an innocent for no logical reason. True, it was a person of interest that met their fate at the hands of the blonde CIA agent, but other than having a daddy that was mixed up with some very bad people, the girl had done nothing wrong.

But then, Sarah hadn't been operating in a "logical" sense in a long time. Not since she started fornicating with Bartowski, at least.

And as much as Casey would have liked to let her fix her own problems, it had been apparent, when he'd spoken to her the previous night that Walker just wasn't interested in trying to make things go away. In fact, her "solution" to the problem ("Put her fucking head on a pike and make Chuck carry it around so all the brunette skanks of the world know he's off limits.") was not only asinine, but kind of scary, because Casey could tell she wasn't joking. Not really.

The veteran NSA agent sighed deeply as he checked his watch – 1:30 PM and still no sign of Walker – and went back to work.

Fifteen more minutes passed by as Casey did his best to bullshit his partner's way out of a reprimand, when the doors to Castle whooshed open. He looked to the top of the steps to see Walker merrily begin to strut her way down into the secret base, all the while loudly singing along to the tune (or more accurately, way out of tune) that was apparently blaring from her earbuds.

"JUST FOR THIS MOMENT, AS LONG AS YOU'RE MINE, I'VE LOST ALL RESISTANCE, AND CROSSED SOME BORDERLINE!"

"Walker," Casey grumbled, but the blonde didn't seem to hear.

"AND IF IT TURNS OUT, IT'S OVER TOO FAST –"

"Walker!" he yelled.

"I'LL FIND THE BRUNETTE SLUT RESPONSIBLE AND KICK HER FUCKING ASS! AS LONG AS YOU'RE MI-NNNNNEEE…!"

"Walker!" Casey bellowed again.

Huffing in frustration, Sarah removed her earbuds and began to stare her partner down. "What is it, Casey?"

"Show tunes Walker? Seriously?"

"It's from Wicked," she explained.

"Yeah, because that makes it better," Casey said sarcastically.

Sarah shrugged. "What? I'm happy," she said, as if that explained everything.

"Happy? How can you be happy? I've been here all day trying to keep you from getting thrown in jail, and you're happy?" he asked incredulously.

"Well, I'm mostly happy because last night, when Chuck got over me killing his whore-bag mark, we had alotta sex. I was a little worried he'd be too much of a pussy after what happened to give me what I need, but my God did he ever rise to the occasion. Three times, in fact."

"Walker," Casey growled.

"And the last time, well, I don't think I've ever had such an intense org-"

"Walker!" Casey boomed. "If I've told you once, I've told you a thousand times…"

"Yeah, I know. You don't want to hear about Chuck getting laid. It makes you want to shoot stuff. Conversely, it's all I really care to talk about, so it seems we're at a bit of an impasse."

Casey shook his head in frustration. Walker had become almost as insufferable as Bartowski at his worst. That said, there were still issues to discuss. "Enough," he said gruffly. "We need to talk."

"'Bout what?" she asked innocently.

"Really? About what? How about we start with you going off the reservation to eliminate a person of interest?"

"Hmm…I don't really want to talk about that anymore," Sarah said. "I think we covered everything that needed to be said last night."

"No, we didn't cover everything that needed to be said. You still haven't given me a good reason for your actions," Casey pointed out.

"Yes I did!" Sarah said defensively. "She had designs on having her way with my man!"

"Your man," Casey began, his agitation beginning to show, "was going to willingly complete his mission, which I'll remind you, is his job."

"Oh, don't worry. I gave him a much better job last night when we were done. In the car. On the way to the hotel," she said cheekily.

"I will shoot you," Casey answered, his voice low and dangerous.

"Oh, I've already been shot. Last night in fact. Chuck shot his –"

"Why do you think I'm joking about this? This is a serious damn problem, Walker. If you can't keep your head in the game, and play by the rules…"

"Then what?" she asked, her own voice starting to show the signs of irritation.

Casey knew he couldn't really force the issue if he wanted to keep his partner with a level head. Or as level as her head got, anyway. Still, she needed to start acting professionally, or Beckman wouldn't hesitate to pull her ass from the project. "Listen, if you can't prove that you can be trusted to do the right thing, you know you won't be around much longer. And I don't need a sulky, moping Intersect."

"She wouldn't dare pull me now," Sarah said.

"Look, I'm not telling you anything you don't already know. Now, let's get down to business. Why did you think it was alright to kill Chuck's mark?" Sarah didn't answer. "Walker? I'm giving you a chance to explain yourself, so hopefully, we can make this all go away. So tell me, why'd you do it?"

"I don't know!" Sarah blurted out. "I honestly have no idea why I had to kill her. I just did. I couldn't help it, Casey!"

Shit. He was going to have to play shrink. He'd been afraid of that when he started his day, but he had hopes that Sarah would at least give him something to work with, but it looked like he was going to have to delve into her history. Like that wouldn't be a headache and a half.

"Walker," he began. "Sarah," he amended, trying to keep his voice as gentle as possible. He knew this wouldn't be easy for her…or for him. "When did this urge to kill begin?" He knew his concern sounded insincere, because it kind of was. You go out, you do your job the way it's supposed to be done, and then you call it a day. That's the way Casey had always lived his life. All this emotional crap was new ground for him.

"Well," Sarah said, seeming to think on the question. "I guess it all started with…you remember that girl Lou?"

"The sandwich girl?" Casey asked.

"Yeah, her. I wanted to kill her. And I wanted to kill Sasha Banacheck. Oh, I really wanted to kill Jill…"

"So pretty much anyone that's had any contact with Chuckles?" Casey asked.

"Yeah, I guess you could say that," Sarah said nodding.

"But you didn't kill them. You did kill this girl," he pointed out.

"I did. It's like, suddenly, I couldn't control it anymore. I used to always be able to push those feelings back, but now…"

"So if I told you that there was some girl chatting up the nerd right now, you'd go into a rage?" Casey asked, his curiosity piqued.

"There's someone talking to Chuck?" Sarah asked, bristling up.

"No, but –"

"Who the hell has been trying to get into Chuck's pants, Casey? You better tell me!" she demanded, grabbing Casey by the shirt collar.

"It was a hypothetical, Walker. Jesus," he said, pulling away from her and straightening his shirt.

"Better be," Sarah grumbled.

So, yeah, now he knew that whatever these urges were, they'd certainly gotten worse. Probably since she started greasing Bartowski's combustibles. But why would that make sense? She didn't have a history of that type of behavior. Certainly she'd never done that when she was with Larkin. She wouldn't have earned her stellar reputation otherwise. But then, there was something in her personal file…

"Let's talk about your mother," Casey suggested.

"No," Sarah answered threateningly. "We're not going to talk about my momma."

"Walker, she's been in prison for murder since you were a kid…"

"We're not talking about my momma!" Sarah repeated, standing to her full height in front of the sitting Casey. "You leave her the hell out of this!"

"But if it's vital to finding a solution –"

"You either drop this, or I call Chuck and tell him about your little issue at birth," Sarah threatened.

"What are you yapping about?" Casey asked. He didn't think there was anything in his agency file that could really do him any damage.

"You know, most men are born with two balls," she answered.

Casey paled. That was his biggest, darkest secret, and that wasn't supposed to be in his personnel file. Hell, unless she got a hold of his private medical history… Dammit, she'd gotten a hold of his private medical history. Stupid fucking CIA! Prying into stuff like that was supposed to be NSA territory.

"I was born with two balls," he said defensively.

"Yeah, but one of those bad boys decided to make a home inside of you, didn't it?" Sarah answered, pressing her advantage.

"Oh, you'd know all about thing being inside of you, wouldn't you, Walker?"

Sarah laughed. If he thought calling her a slut was going to make her back off, he was wrong. "The only thing that's been inside of me lately is Chuck's big, thick –"

"Fine! We won't talk about your mother!" Casey said, cutting her off.

"That's what I thought," Sarah said with a smirk, and she began to make her way back to the steps.

"Where are you going? We're not done here!" Casey shouted to her retreating form.

"Oh, we're done here," Sarah corrected. "I was just stopping by to say 'hi' on my way to the Large-Mart. Chuck and I are out of condoms again. We've really been burning through those suckers lately."

"Walker…"

"Yes Casey?" she asked sweetly.

He sighed. "Get the hell out of here, and keep it in the privacy of the bedroom, please?"

"You got it, Casey," she said as she skipped back up the steps and out of Castle.

A/N: Hope you enjoyed it, and thank you so much in advance for all the reviews I know you'll give me ;-) You guys are awesome. Peace.