Dean Winchester paces the interrogation room, running a hand through his hair.

"Well, he's obviously nervous," says Sweets, from inside the observation room.

"No, really? I didn't need a psychologist to see that, Sweets." Booth shoots his friend a look, then turns back to their suspect. "Care to elaborate?"

Sweets shakes his head. "I can't make any sense of it. The Feds have caught him before, a couple of times. I read through the psych profiles from those interrogations. He's always been cocky, cool, and collected. What's different about this time?"

"We didn't catch his brother," Booth says. "In the past, they've always been arrested together. That's what's different. Well, the brother is supposedly dead, but so was Dean, and he's alive and kicking. Odds are, Sam Winchester is alive too."

"But you did catch him with an accomplice, didn't you? That's new." Sweets looks over the file he'd been given. Booth had called him in only half an hour ago, offering up the prospect of an alleged serial killer in need of psychoanalyzing. That kind of temptation couldn't be turned down. So here he was, with just enough time to skim the files before the interrogation.

"Yeah. I guess that part is new. I've never seen the accomplice before, not on any wanted lists. Angela's scanning the missing persons database now."

"Okay, so that's what's different. For some reason, the fact that you've taken this John Doe into custody is seriously freaking out our suspect. But why?"

"One way to find out." Booth heads for the door, and Sweets starts to follow. "No, you're staying here."

"But I've got questions-"

"Not another word. He's a serial killer. I'm not taking any risks here. You can suggest questions to ask him over the Bluetooth." Booth taps his ear.

Sweets surrenders and settles down in front of the mic. He watches Dean Winchester's body language, taking notes, analyzing the nervous tics.

Dean is clearly very riled up about something. He can't seem to sit still for very long. He mutters unintelligible things to himself. Sweets wonders what it is about the accomplice in custody that can shake up Dean Winchester. He's heard rumors of the Winchesters in the psychiatry community – completely unmovable by any interrogation technique, and of course, modern Houdinis. Sweets is eager to analyze the older brother for himself.

A moment later, the door to the interrogation room swings open. Booth walks in and says, "Special Agent Seeley Booth. Please, Mr. Winchester, sit."

"Hell no," says Dean, his first words since his arrest. But he stops his pacing and gives Booth a funny look. "First question: why am I walking free?" He wiggles his uncuffed hands.

Booth shrugs, nudging aside his suit jacket to reveal a gun holster. "I've got a gun, you're unarmed. I'll take my chances."

Dean cocks his head to the side. "A good soldier never underestimates his enemy."

"And are you my enemy, Mr. Winchester?" Booth says. His tone is casual, but with something harder underneath.

"That's up to you."

"But you are a soldier, if this file of yours is anything to go by. Quite a record you've got here, Mr. Winchester." Booth flips through the fat manila file absently.

Dean just stares at the agent unflinchingly. "Yes sir, I am a soldier." He ignores the comment about his record.

Sweets notes, Respects authority. Refers to Special Agent Booth as "sir."

"As am I, Mr. Winchester. I won't put up with your usual nonsense."

"Which force?"

"United States Army, 101st Airborne Division, Special Forces and 75th Ranger Regiment. Like I said, don't try anything funny."

Dean nods and straightens a little. "I respect that. My father was a Marine."

Sweets already knew that from the file, but Dean's words tell him something else too. Refers to father in the past tense, he writes. Then, into the mic, he says, "Booth, he said was. Ask him what happened to his father."

Booth clears his throat. "And where is your father now, Mr. Winchester?"

Dean folds his arms. He's calmed down some since Booth entered the room, but he still fidgets nervously. "I'm not telling you anything. Not until you let me see Cas."

Booth straightens up. "Cas? I assume that's your accomplice's name."

"Yeah, that's him. I want to see him."

"I'm sure we can arrange that, Mr. Winchester, if you'll answer some of my questions."

"No. I'll see him first, then we can talk." He glances towards the one-way mirror, then back to Booth.

"He's unstable, Booth, but he's not lying," says Sweets. "He's really just desperate to see his friend."

"Sit down, Mr. Winchester." Booth uses his authoritative voice, the kind he uses on dangerous missions. Dean complies immediately.

Sweets underlines his previous comment about authority and adds, Militaristic obedience of orders. Probably instilled in him by Marine father.

Booth sits across from Dean and folds his hands on the table. "So, tell me more about this Cas guy."

"I'm not debating this. You let me see him, or I'll tell you nothing."

Sweets doesn't doubt this. Dean is stubborn. "Booth, maybe we should…"

Booth ignores him. "Mr. Winchester, we found you breaking into the Jeffersonian and destroying evidence from a homicide case. You're already held accountable for several charges of murder, among other felonies. We don't have to listen to your request. We can bury you in the system, and you'll never see Cas again. You'd benefit by answering my questions."

Dean takes a ragged breath. "Yeah, okay, but that doesn't mean I'm going to. Seriously, dude, I just want to see him. You can supervise and everything. Please."

This contradicts everything in Dean Winchester's file. He's supposed to be composed, with a witty retort to every question. He shouldn't have batted an eyelash at Booth's threat. Something about this Cas fellow is really getting to him. His tone of voice is urgent, desperate.

Besides, since when does Dean Winchester beg for anything?

Sweets leans forward to the mic and says, "Booth, get in here. I've got an idea."

Booth hesitates, shifting his weight. "If we let you see this man, you'll talk to us?"

"For God's sake, sure. Whatever. Just…" Dean rakes a hand through his hair. He looks unsure of himself. Something is definitely wrong.

Booth nods and rises from his chair. "I'll consider your proposition."

In a moment, he's back in the observation room. "What, Sweets?"

"I think we should let Dean see his accomplice."

"Are you crazy? You want to let two serial killers convene?"

"Well, we don't know that Cas is a serial killer. And anyway, yes, I do."

Booth throws his hands in the air. "Okay, why?"

"Look, Dean is acting uncharacteristically. Differently from how all these psych profiles say he should be. I think it has to do with this Cas fellow."

"You think? Of course it does. He won't shut up about the guy."

"Exactly. And I think if we want to find out anything, we've got to figure out what their dynamic is. Why Cas is so important to Dean."

"I don't understand."

"Look, if we leave them alone together, they'll start talking. We'll see what their relationship is like. We'll see why arresting Cas has upset Dean so much. The accomplice could be a helpful bargaining chip against the Winchesters."

"Yeah, okay, that's not a bad plan. And we can watch from here."

"Do you want to bring Bones in to watch? They were desecrating her evidence, after all."

Booth laughs and shakes his head. "No, that wouldn't be a good idea. She's furious. We let her anywhere near Dean Winchester, I'm afraid she'll be the one going serial killer."

Then Booth radios security and requests that they bring the John Doe in custody up to the interrogation room.

"Should we talk to him first? I mean, we don't even know if his name is Cas. Or if it's a nickname. We don't know anything."

"This was your idea," Booth says. "Let's just… see how it plays out."

They turn again to watch the interrogation room, where Dean is, once again, pacing. At one point, he turns to the window.

"I know you're back there," he says, pointing in their general direction, "and if you've hurt a hair on his head, I swear I'm gonna- fuck!" He curses and runs a hand down his face.

"Look at him," Sweets says, "he's out of control. He's really worried sick about his friend. I mean, Dean Winchester has never batted an eyelash at being arrested before. But this time's different."

"Hmm." Booth watches the guy carefully. "What do you think he was doing at the lab, Sweets?"

Sweets shrugs. "Honestly? I don't know. I mean, we know what he did. But I don't know why."

Booth makes an exasperated noise. "He doused the bones in salt and gasoline. Who does that? Those bones were our only hope of solving this case, and now…"

"Hey, at least we caught him before he lit them on fire. Grave desecration is pretty high up on his list of charges. Salting and burning bones."

"What do you think he's doing?"

"I haven't looked deep enough into his case file. But it's something to do with the occult, I think. He's a weird one, I'll give you that."

"Bones is on the warpath. She wants him in jail for life."

"That's an overreaction, don't you think?"

"He ruined a lot of our evidence," Booth points out. "I'm pretty angry, myself."

"But he's not even thinking about his crime right now." Sweets nudges his friend to watch Dean. "He's entirely focused on seeing Cas. It makes you curious, doesn't it?"

"Yeah. I'm getting impatient for this to go down."

As if on cue, a security guard opens the door to the interrogation room. Dean's accomplice is pushed inside, and then the door slams behind him.

"Cas!" Dean says, immediately going to his friend.

Cas is plainer than Sweets expected, with dark, rumpled hair and a tattered trench coat. His blue tie hangs limply around his neck. Not at all what Sweets expected. He thought he had a basic understanding of Dean Winchester, and the kind of people with whom Dean associates. Apparently not.

Dean looks at Cas like he's an angel sent from God. "Are you okay?"

"I'm fine, Dean." His voice, too, is unexpected, low and gravelly. His words are perfectly steady.

"I didn't mean for you to- Jesus, Cas, I'm sorry."

Cas shakes his head. "Dean, it was not your fault. Our… B&E, as you would say, was poorly timed."

"Yeah, but you've never been in trouble with the law before. You were our one get-out-of-jail-free card," Dean jokes.

That's the Dean Winchester represented in these files, Sweets thinks. Riddled with pop culture references and confident as Al Capone.

Dean hovers by Cas, still on edge. "You're sure you're okay?"

"Yes, Dean. You don't need to worry about me." Cas crosses the room to sit down. Dean follows him, kneeling at his feet. He wraps both hands around Cas's wrists.

"Yeah, but I do anyway. You're a lot more fragile now. You won't heal if you're hurt, Cas. That scares me."

"I can defend myself," he says, a little sullenly.

Dean holds up his friend's wrists. "Really? Then what are these scrapes on your wrists?"

Cas avoids Dean's skeptical look. "The FBI agent who arrested me may have been a little rough with the handcuffs. It was nothing."

"Nothing? Son of a bitch, I'm going to kill him."

Cas gives his friend a warning glare. "Dean. You're in police custody. Refrain from saying things like that."

Dean quiets. He rubs the scrapes on Cas's wrists with his thumbs.

Interesting, Sweets thinks. Dean Winchester listens to nobody, but he listens to this man. Cas is really something. A friend, then, a really close friend. Perhaps a new acquisition? Nobody's heard of him before today.

Cas is Dean Winchester's weakness. That much is obvious. This can be used against Dean for information, certainly.

Booth seems to be thinking the same thing. "Wow, I didn't know serial killers actually cared about people."

Sweets snorts. "Oddly touching, isn't it? It says here Dean is protective of his little brother. I suppose the quality carries over with this man."

"An overly protective serial killer. Who would have thought?"

"They threatened you," Dean says quietly, and it draws back the agents' attention. "Nobody gets to do that. Not anymore."

"I'm not made of glass, Dean. I've gotten hurt before. You know that."

"Yeah, but it's different now."

Cas rolls his eyes. "If you're going to freak out over a couple of scratches…"

"I was just worried about you, okay? Last I saw they were placing you under arrest. Anything could have happened. You're new to this. I got worried."

"I can tell. But Dean, I really am okay. You can relax now."

Dean still hasn't let go of Cas's hands. Sweets makes a note of that. The bond between them goes deeper than he originally imagined. Best friends, then. Maybe even closer than Dean and his brother.

"I'm going in there," Booth says, and he does.

Both men jump as Booth enters the room, and Dean rises to his feet.

"What do you want?" he says.

"We made a deal." Booth sits down across from them.

"You hurt Cas. That's not cool." Dean's hands ball into fists.

For a moment, tension crackles in the room.

"Dean," Cas says quietly. The one word holds weight. Dean turns, meets Cas's eyes, and something unspoken passes between them.

"Yeah, okay," Dean says, and calms down.

"Thank you," Booth says to Cas. "Mind telling us a bit about yourself?"

"My name is Castiel," he says.

Ah. So "Cas" is just Dean's nickname for him. And what kind of name is Castiel?

"Nice to meet you, Castiel."

Dean crosses his arms. "Hey, how come you weren't this polite to me?"

Booth fixes him with a look. "You're wanted for murder in three states. Castiel has done little wrong. You were, after all, the one carrying the salt and the lighter."

Dean shrugs. "Fair enough."

"Anyway," Booth continues, looking back at Castiel, "how did you meet Dean Winchester?"

Castiel looks at Dean, blue eyes wide. Very unsure of himself. Dean raises an eyebrow. It's subtle, and Sweets would have missed it if he wasn't looking for tells. These two communicate well. Maybe they've known each other for longer than he estimated.

Honestly, Sweets just can't figure out their relationship. First he thinks it's something new, then something old. They're close, but they bicker. Dean is protective of Castiel, yet Castiel can tell him what to do. Nothing adds up.

Dean answers instead. "We met a couple of years ago, in Illinois. My car broke down, and I caught a ride from him."

Booth glares at Dean. "I'd like to hear it from him, if you please. Castiel?"

Castiel nods, but doesn't quite meet Booth's eyes. "Dean is correct."

That's a lie, Sweets thinks. He wonders how they really met.

"And were you aware, when you broke into the Jeffersonian early this morning, that you were working with a criminal?"

"Yes." This time, his gaze is even. He tells the truth.

"But you didn't mind?" asks Booth.

"Of the major crimes, Dean is innocent. As for the minor issues, God will absolve him of these crimes. Dean is a good man, a righteous man. He has done much for humanity, and I understand that he has had to… cut sides with the law."

Dean coughs. "Corners, Cas. Cut corners."

"Yes. What he said."

Booth leans forward. "You said 'God will absolve him of these crimes.' Are you a religious man, Castiel?"

Dean promptly bursts out laughing. It's the loud laughing, the kind that quickly turns to hacking and coughing.

A smile quirks at the corners of Castiel's mouth, but nothing more. "Yes, I daresay I am."

Sweets isn't sure what's so funny about the question.

Booth ignores the reaction and focuses his gaze on Dean, who's sobered up. "Mr. Winchester, why did you break into the Jeffersonian last night to burn a skeleton?"

"I'm not the murderer, if that's what you're getting it."

"You can see why it places you on our list of suspects."

"Yeah, but that's not why I was there. I'm like you, Agent Booth. I'm trying to save lives."

"You're not very good at it, Mr. Winchester. Murdering civilians in St. Louis?"

Dean averts his eyes. "That wasn't me. I tried to stop it."

Sweets feels his breath falter. Dean isn't lying. The aversion of his gaze, while usually a tell, is more than that here. It's regret, embarrassment. Maybe even guilt. Dean honestly believes in his own innocence.

Well, that will make for an interesting court case. Sweets makes a note of it – he'll think of that reaction in more depth later.

Castiel places one hand on Dean's arm. "That was years ago, Dean. You can't save everyone."

Dean rolls his eyes and snaps, "You think I don't know that? I, of all people?"

The room goes quiet for a moment.

Then Booth says, "What do you mean by that, Mr. Winchester?"

"Nothing. Forget it." He shrugs off Castiel's arm.

Their friendship is going through a rough patch, then. Sweets still can't figure it out. All he knows is that Dean was worried out of his mind before. Now that Castiel's at his side, he's calmed down immensely. He's gone back to the Dean Winchester described in the files – cocky, cool, and collected. Still, there's something edgy about him, something vulnerable, that the psych profiles never mentioned.

"Where is your brother, Mr. Winchester?" Booth asks.

Dean looks up, emotions concealed well. "What?"

"In the past, we've always arrested you two together. This time, we found Castiel instead of Sam. Where is your brother?"

"According to your records, he died a few years ago."

"According to our records, so did you. They're not proving to be very reliable. I'll ask one more time, Mr. Winchester. Where is Sam?"

He smirks. "Probably finding a way to bust us out right now."

Booth sucks in a breath and leans back. "Sweets," he says, addressing the one-sided mirror directly, "remind me to double security when we're done here."

Dean snorts. "What the hell kind of name is Sweets?"

"What the hell kind of name is Castiel?" Booth retorts.

"Yeah, I asked him that too."

"Sounds biblical," says Booth.

"It is. In every sense of the word." Castiel smiles slightly.

Sweets hates this. He's supposed to understand people; that's his job. But with these two, he feels like he's missing key pieces of a puzzle. They've got inside jokes, hidden emotions, unspoken communication. They know something he doesn't.

Castiel fixes a cold gaze on the agent. "You are a devout man, Agent Booth. Do you trust religion?"

Booth is taken aback by the question. "Yes, I do."

"Then trust me. Dean Winchester is an innocent man, and you are on the wrong side of history by detaining him here. He and I are trying to save lives."

Booth looks a little uneasy. "You almost completely destroyed my partner's evidence. You've made solving a woman's murder nearly impossible. I don't see that as saving lives."

"You save lives, Agent Booth, do you not?"

"I like to think so."

"And have you ever shot someone in the line of duty?"

He stops and leans forward. "That's different."

Sweets is impressed. Castiel has gotten Booth to answer questions unthinkingly, reversing the roles. He'd make an excellent psychologist, in another life.

"You know, in your gut, that Dean is innocent."

"The law says otherwise."

"The law is wrong," snaps Dean.

Booth looks a bit like he's drowning. "The law is never wrong."

Sweets understands. Booth has lived his whole life by one principle. He's killed people and gone on with a clean conscience because he believes that what he's done is right. He follows the law, and that justifies his actions. For these two unsettling men to tell him otherwise…

"Don't listen to them," Sweets says. Booth still has the Bluetooth in his ear turned on. "They're messing with your head."

Booth straightens, recomposing himself. He heard Sweets's words. "We're done here." He signals for security, and the door opens.

"What are you doing?" asks Dean, looking nervously from Castiel to the security guards. "Are you taking him away?"

Booth stands up, now at eye level with Dean. "You didn't think we'd leave you together unsupervised?" He smiles slightly. "Your brother will have a much more difficult time making two separate rescue missions."

Dean raises his chin, facing the challenge. "He'll do it."

The security men grab Castiel, one on either side of him, and start to lead him towards the door.

"Wait," says Dean.

He strides forward, grabs Castiel by the collar of his coat, and pulls him in for a kiss. Castiel seems to have been expecting it, because he immediately kisses Dean back.

Sweets feels his jaw go slack. The security guards immediately jump back a few feet. Booth, too, is staring at the men in shock.

Dean pulls away first, a little breathless, and grins. "I'll see you soon."

Castiel smiles back. "I know."

Dean lets go of the front of the trench coat, and the security guards lead Castiel out. Once they're gone, Booth finally recovers.

"I'll, um, need to take you to your jail cell now." Booth looks almost embarrassed at seeing that. He avoids Dean's triumphant gaze as they leave the interrogation room together.

It takes several moments for Sweets's brain to begin functioning again.

He was so wrong about the nature of Dean and Castiel's relationship.

(In the morning, both jail cells are completely empty, not a trace of either man left. Booth punches a hole in the wall when he hears the news.)