Dean waits until he hears Charlie's chair scrape across the war room floor; until he hears her speaking in hushed tones to a half-woken Sam, before he hits call.

Castiel answers immediately, as if he'd been waiting, and Dean remembers reading about him standing on the shore of Lake Michigan willing his cell to ring. It sets something fluttering in his chest to think he might have been doing the same thing again, and he can help but smile.

"Hello?"

"Hey, Cas."

"Dean?" Castiel asks, as if confused by the voice he's hearing.

"You expecting someone else?"

"The screen said The Queen is calling."

With a laugh, Dean sinks down onto a stool at the counter.

"This is Charlie's cell."

"Oh," Castiel says, pausing briefly, "I thought you were going to call from your new phone so I'd have the number."

Dean blanches. In all his eagerness to call Castiel, he'd forgotten what his excuse had been. He knows there's a spare cell lying around in the bunker somewhere, but he has no idea what the number is.

"Right," he says, clearing his throat, "yeah. Uh... I haven't, uh... I mean I didn't get one yet. But I said I'd call when I got home, so—"

"I'm glad you did."

There's warmth, sincerity, in Castiel's voice, and Dean relaxes, smiling down at the counter top. He thinks about saying me too, but he's pretty sure that's obvious.

"Did you get in touch with Chuck?" he asks instead.

"Yes. He seemed fairly confident that he'd be able to decode the tablet, and he's on his way to you as we speak."

"Good. He'll be safer here."

It takes a lot of self control to not mention that Castiel would probably be safer here, too, but he manages to stop himself. It's pointless to even suggest it. No matter how much warding they put up, the risk of the other angels tracking him is too great, and he knows Castiel would never agree to it if there's even the slightest chance that he would be putting them in harms way.

Castiel sighs, and Dean hears the rustle of fabric as though he's slouching, slumping forward in his seat. The mental image is unsettling. The idea of Castiel being tired at all is unsettling.

"You still doing okay, Cas?"

"For now. But I need you and Sam to help me with something, if you can."

"Yeah, whatever you need. I'll get Sam... just a sec."

Dean walks out into the war room, where Charlie is sitting at her computer and Sam is leaning from beside her, reading something on the screen. They both look up when he enters, and Dean taps a button on the cellphone.

"Alright, Cas, you're on speaker."

"Hello."

Sam and Charlie respond at once; Sam's voice still a little rough from his earlier coughing fit, Charlie's uncharacteristically shy.

"How's it going, Cas?"

"Hiya."

"I'm well," Castiel replies to Sam before asking; "who else is there?"

"That would be Charlie," Dean tells him.

"The Queen?"

"Wow, I like you already," Charlie says, grinning at the phone, and Dean rolls his eyes.

"It's just a nickname, Cas."

"Oh."

"Don't listen to him," Charlie says, still grinning, "I'm definitely royalty."

Sam snorts out a laugh, and Charlie fixes him with a look, challenging him to deny it. He holds up his hands in surrender.

"Yeah, definitely royalty, Cas," he agrees, and Charlie crosses her arms, smirking.

"Damn right."

"So," Dean says over them, "crib notes; Cas has the angel tablet and he's gotta keep moving or it's gonna blow. He's basically the bus from Speed."

At the mention of exploding, Sam and Charlie end up with matching expressions of concern on their faces. Castiel meanwhile, his voice hollowed by distance, asks quizzically, "What do you mean, I'm a bus?"

"It's a—forget it," Dean says, rubbing at his forehead, "what do you need us to do?"

"I'm running out of Biggerson's."

"Come again?"

"My evasion technique has been working so far because each restaurant is basically identical. But there are slight differences. The views from the windows, the number of tables—"

"Wait, what evasion technique?" Sam asks.

"It's a little complex," Castiel says, pausing to think of a way to explain it, "Are you at all familiar with the work of Erwin Schrödinger?"

"The physicist from Austria?" Sam asks.

"That's the guy with the dead-not-dead cat, right?" Charlie asks, though from her tone it sounds like she already knows.

"Yes," Castiel says, and Dean narrows his eyes first at Sam and Charlie, then at the cell phone, because apparently everyone but him studies physics for fun.

"So you know random Austrian physicists but you've never heard of Speed?" Dean asks, incredulous, "That's it. When you get back, you've got some holes that seriously need filling."

Charlie snorts into her hand and Sam turns beet red with repressed laughter. Dean flushes, rolling his eyes.

"That's not... you know what I meant."

On the other end of the line, Castiel is oblivious. Dean is relieved.

"So you undertand the basic theory?"

"Yeah," Sam says, wiping silent tears from his eyes.

"I am the cat. Biggerson's is the box."

"You're alive and dead?" Charlie asks, resting her elbows on the table and frowning.

"More like everywhere and nowhere, but that's the basic idea."

Sam's nodding as he figures it out, and he leans closer to the phone, clearing his throat.

"Okay, so... The more familiar you and the other angels are becoming with each location, the less it's working because it's no longer an identical room but a similar one?"

"Essentially, yes. What I need is for you to find me a new box, so to speak. Someplace with many locations that all look alike."

"Can't you just keep appearing here and stare at the wall?" Dean suggests, knowing how pathetic it sounds but barely caring.

He pointedly ignores the judgemental look he gets from Sam.

"I don't think that would work," Castiel says carefully, and Dean sighs.

"I figured."

"Though obviously I'd rather be there," Castiel adds after a moment.

"Yeah, I know."

There's a brief, slightly awkward silence, and Sam coughs into the crook of his elbow. Dean can't tell if it's from discomfort or his trial sickness, and he's about to make another, probably useless suggestion, when Charlie speaks.

"I've got an idea," she says, raising her hand as if she's in a classroom, and Dean looks away from the phone to see her hopeful expression. "How about cinemas? I mean, there's got to be tens of thousands of them all over the world, and even if they're run by different companies, they all look pretty much the same."

"Plus it's dark, so anything that is different will take a lot longer to notice," Sam adds, sitting up straighter in his seat, "I think she's onto something, Cas."

"I think so, too. Thank you, Charlie."

"Hey, however I can help," she grins, and Dean claps her on the shoulder.

"You know Cas, I wouldn't have even found you tonight if it wasn't for Charlie."

"Then I owe you a great deal more gratitude," Castiel tells Charlie.

Dean kisses the top of her head, and she squirms away, embarrassed.

"Jeez, guys, quit it," Charlie says, going bright red and sinking down into her seat. Dean shoves her shoulder, laughing.

"I'll need to fly again shortly," Castiel announces, "Sam, Charlie, if you don't mind I'd like to speak privately to Dean first."

"Sure, no problem," Sam says, waggling his eyebrows at Dean, and Charlie suppresses her laughter, "look after yourself, Cas."

"That's the idea."

Dean glares at both of them, though his heart isn't in it, and switches speaker off before walking back into the kitchen.

"What's up?"

"I was looking through the photos on your phone earlier."

For a few seconds, Dean's eyes go wide, and he tries to remember if there are any pictures on there he wouldn't want Castiel seeing—he knows for certain there were a few photos on his old cell that he definitely would not have wanted him to see—but he's been practically celibate since they got back from Purgatory, and he's pretty sure his cellphone camera roll reflects that. The panic barely has a chance to kick in before Castiel goes on.

"You took pictures of me in Oklahoma," he says, though it sounds a little like a question, and Dean holds his breath waiting for the rest of it.

Castiel seems to be waiting too. They are both silent for far too long.

"Dean? Are you still there?"

"Yeah. Yeah, I'm here."

"Why did you take those pictures?"

Rubbing at the back of his neck, Dean shrugs uncomfortably.

"Y'know," he says, though he's almost positive he's going to need to explain it, "just in case."

"In case what?"

"In case something happened. In case you left again."

"I did leave again."

"Yeah."

"But having the pictures made up for it?"

"Not really," Dean admits with a miserable laugh, "looking at them hurt like a bitch."

"Oh."

"Still glad I had 'em though. Was nice to see you even if I couldn't see you, you know?"

As absurd as it seems, Dean's sure he can hear Castiel smiling.

"It's like when I think about your prayers," he says, understanding.

"You think about my prayers?"

"Of course. Every day. Dean, I—" Castiel stops, and Dean pictures him looking into the middle distance, the way he does when there's something coming through on angel radio. When he speaks again, he sounds dismayed. "I have to go."

"I'll send you a message when I have the new number."

"Goodbye, Dean."

Dean doesn't like how final that sounds, and he almost says something when Castiel adds; "I'll see you soon."

After he ends the call, the silence in the kitchen is overwhelming. He makes his way out into the library to find the spare phone. As he goes, he sends out a quiet prayer.

Soon isn't soon enough.