A/N: Hi, everyone! I'm back! :D So, disclaimer for all you Cole lovers out there, I'm so sorry. I actually don't dislike him in canon, but I needed to borrow him as a bad guy, so... yeah. Don't hold your breath for him to turn into the good guy, because this is an AU and he doesn't. Other notable differences in this AU: it takes place after the season 9 finale, so Metatron has been captured and Abaddon is dead, but Dean wasn't killed and didn't turn into a demon. He does still have the Mark of Cain. Cas still has Theo's grace and is still off on his own getting sicker and weaker, but never went hunting with Sam (who doesn't have a broken arm).

I don't own Supernatural characters. They belong to Kripke and Co. Some of the dialogue comes straight from the episodes Black and Reichenbach.

A million thanks to Aini NuFire for being a constantly helpful and supportive beta reader and writing buddy :)

"Damn it, Dean, I don't care! You need to come home!"

Sam paced the Bunker, walking between the rows of bookshelves in the library. He pinched the bridge of his nose. At the moment, he would rather chuck the phone across the room than listen to one more slurred excuse from his brother.

"Because this is stupid, and you're getting careless!" he shouted in response to Dean's question. "I get it, you want to go on hunts and drink yourself to death, that's probably the Mark talking! You're lucky that demon at the gas station didn't finish you off. They caught it on the security camera, you know. I'm having to clean up your messes."

Why couldn't his stupid brother just come back to the Bunker? Sam hadn't seen him in over a week now, and this was the first time in three days Dean had bothered to answer the phone.

"You know what- no! Dean, no, not one more hunt- a nest of what? Fine, but come home and sober up first, and I'll go with you."

Even as he suggested it, though, Sam knew Dean wouldn't be coming back, not yet. Their fight against first Abaddon and then Metatron had left the hunters shaken, especially with the near miss for Dean before he could take down the scribe. Sam had thought his brother was dead for sure, and only by the grace of God had he survived.

But the Mark had already wreaked too much havoc on Dean's numerous complexes. Sam knew the older Winchester was avoiding the Bunker and him because of the guilt over what he was slowly turning into—merciless, cold, and brutal. And it was all because of that damn Mark.

Just one more reason Dean should wait for him, though, so Sam could help pull him back from the edge if he needed to.

"Dean, please just- yeah, I know I've taken off to hunt on my own before." Sam ran a hand through his hair, shaking his head. Of course Dean would bring that up now. "I get that you need time to deal, but I don't see how this is helping- wait! Dean, don't hang up! Just…" The hunter let out a sound of frustration, turning to pace back the other way. "Just give me a time that you swear you'll check in by so I can come after you if- a week? How about tomorrow-"

It was too late. Dean had hung up and Sam knew better than to think his brother would answer the phone again if he tried to call back. Why did Winchesters have to have such a stubborn streak? Sam knew Dean could handle whatever he was up against—if anything, he was afraid Dean might handle it a little too well.

But it only took one mistake, and being out of communication like this was just stupid.

Sam sighed and tossed the phone on one of the library tables, rubbing his face and looking around. It wasn't like he didn't have plenty to do here, with so much lore that he could delve into and try to start cataloguing.

It was hard to focus much on the old books, though, fascinating as they were, when his mind was wrapped up in worry for his brother. Sam needed some kind of distraction.

Frowning, the hunter glanced back to the desk, regarding his phone for a second before moving over to pick it back up. Turning the screen on, Sam thumbed through his contacts list. He could see how Jody was getting on with Alex, or… it'd been a while since they'd heard from Cas.

Sam sank down into one of the chairs, debating whether or not to call the angel. Cas was worse about checking in than Dean was. After defeating Metatron, allowing the angels to return to their home, Cas had come back to Earth. Then he'd just taken off, something about finding any remaining angels and trying to encourage them to return to Heaven.

And that was it. How long had it been since he'd talked to Cas? Sam winced, realizing it must have been going on a month now. He should have done a better job keeping in touch. For that matter, Sam thought with even more chagrin, he should have just insisted from the start that the angel continue to use the Bunker as his home base. If he hadn't been so worried about Dean, maybe he would have pushed the matter more instead of letting it and Cas go.

Sam's resolve hardened and he pushed the button to dial the angel's phone.

It took a couple of rings, but then Cas's gruff voice answered at last.

"Sam. Is everything alright?"

"Yeah, hey, Cas," the hunter replied, leaning back in his chair and staring at the Bunker ceiling. "Just thought I'd check in on how things were going. Dean's off god knows where trying to kill his liver by Friday."

"He's… what?" Cas asked between a few coughs. "Is he okay?"

"Dean's just… being Dean. He's got a lot of stuff to work through. I think now that Abaddon is dead, which was the whole point of him getting the Mark, we really need to start thinking about how to get that thing back off of him again. And I'm about one more ignored call away from holding an intervention." Sam bit his lip, then added, "Might not hurt to have you here as backup, you know? Do you have anything going on, or…?"

"No, I-" the angel cut off in another fit of hacking coughs, each one making Sam frown a little more.

"You alright? What, did Dean rub off on you that much, you're hanging out in smoky bars now?" But that couldn't be right, not unless Cas had found the quietest dive bar in existence. There was no background noise. So what was making him cough like that?

"I'm fine," the angel replied a little too quickly. "Just, uh... swallowed something wrong."

Sam sat up straighter. "Wait, you're eating? Didn't you say everything tasted like molecules? If you're eating, does that mean you're losing your grace again?"

"No. Uh, yes. Yes, it does taste like molecules, you're right. That's probably why I was choking on it."

A cold knot started to work its way down Sam's throat, settling in his gut like a lead weight. He swallowed, listening as Cas coughed again and couldn't seem to stop. The sounds grew weaker and weaker until the angel was left wheezing for air.

"Cas," Sam snapped. "You know you're the worst liar I've ever known. What's going on? Are you sick?" But that couldn't be, surely. Angels… angels didn't get sick. They didn't have coughing fits like that, or sound like they barely had enough energy to keep up the conversation.

"No," Cas whispered, but the labored breaths Sam heard told a different story. "Everything's fine, don't worry-"

"Yeah, bullshit!" Sam was already on his feet and storming towards the Bunker's garage. His heart pounded, even more flooded with guilt that he'd waited so long to check in with his friend, after complaining to Dean about doing that exact same thing. "I'm on my way. Where are you?"

The angel sighed. "Sam… you have more important things-" He broke off to cough some more, then took several more deep breaths.

"No," Sam snapped as he jumped into his Dodge Charger. "Cas, you're sick. There's nothing else more important." Even if they'd been in the middle of something, which they weren't, this took precedence. Pulling out of the Bunker's garage, Sam punched the gas, heading towards the road with gravel spewing behind him. "Either tell me where you are, or I'm gonna pull up your GPS and come find you anyway."

The hunter heard another sigh, then a few softer coughs. Finally, Cas murmured, "Ness City. The, uh… Redbird Motel."

"Ness City," Sam repeated with a frown. "Okay. That's only about two and a half hours from here."

"Okay. I suppose I'll see you when-"

"Cas, wait," the hunter interrupted before Cas could hang up on him. "Stay on the line, man." He was trying not to blow things out of proportion, wanting to believe Cas when he said things weren't that bad. But this wasn't okay. The cold prickle that wouldn't leave his skin backed him up on that, as did Cas's silence instead of more argument.

Finally, the angel whispered, "Alright."

Sam nodded, spinning the wheel one-handed to veer onto the state road. "So, uh, talk to me. How's everything going with the angels?"

"As you might expect," Cas gritted out. "Some were willing to listen to reason. Others… others were not. I told Hannah to go on without me and continue working."

"And she did?" Sam snapped, trying to smooth out the bite in his tone, but annoyed that the other angel would have left Cas alone in the condition he was clearly in.

"I told her I would catch up. I seemed fine when she left…"

He trailed off, and Sam's heart stuttered. So Cas was admitting that he really wasn't fine at all, as though Sam could remotely be fooled. It still seemed like Hannah would have checked in with Cas by now, but then again… Sam hadn't. Dean hadn't.

Dean…

Sam bit back a curse, realizing that he ought to let Dean know what was going on, but unwilling to hang up on Cas. Besides, his brother was busy on a hunt and wouldn't answer the phone even if Sam did call. He'd have to leave a message anyway, so there was no reason to bother until he'd found the angel.

Urging Cas to keep talking, Sam stayed on the line as the miles rolled by under the tires. When it became obvious that this was wearing the angel out even more, he traded some stories of his own, though didn't mention his concern for Dean again. No reason to add more stress to the angel's plate. All the while, Cas couldn't seem to hold back those horrible coughs that made Sam's entire body ache just to listen to.

He wondered again what exactly the problem was… and what they were going to do about it. If the grace Cas had stolen was affecting him, they could always try removing it. It would be excruciating, which made Sam ache even more, and it would condemn Cas to humanity once again, but surely that was better than a slow, crippling death.

But what if that tattered grace was the only thing keeping Cas alive?

They would deal with it later. For the meantime, Sam pushed it from his mind so he could concentrate on staying as calm as possible for Cas's sake.

They kept talking as Sam pulled over for gas and ducked into the station to get some Tylenol and water bottles for Cas. By the time he hit the road again, his cell phone was down to half the battery, but there was only about an hour to go.

"Alright, I'm not too far now," Sam assured Cas, turning on the speaker phone so he could check the map again once he was well onto the road. "Just hang in there a bit longer-" He cut off with a groan as the car suddenly sputtered, then died completely. "Aw come on, what the hell?"

"Sam?"

"Just something with the car," he assured the angel, stomach twisting as he prayed this wouldn't delay him reaching Cas. And of course he'd taken a back road shortcut… there weren't even other cars around that he could jack one. Biting back a frustrated grumble, Sam popped the hood and slid out of the Charger.

"What's happening?" Cas asked. "Sam?"

"Hang on a sec." Sam leaned over as he saw another car pulling to a stop behind him. Thank goodness… maybe if this wasn't a quick fix, he could catch a ride to somewhere he could just swipe another set of wheels.

A man climbed out of the car, nodding to Sam. "Hey. Need some help?"

"Uh," Sam glanced down at the engine, wishing he had Dean there with him. Dean was the mechanic; the little bit he'd taught Sam was for the Impala, which didn't look the same. "Yeah," the hunter admitted. "I think so. It just died on me."

"Out here?" the guy asked, glancing around the deserted road, raising his eyebrows.

"Yeah." Tell me about it.

"Your ride really has it out for you, huh?"

"I guess so," Sam said with a snort as the stranger approached and pointed to the open hood of the car.

"Give you a hand with that?"

Sam stepped back a bit, gesturing as well to the engine. "Yeah, I'd appreciate it. Thanks." He fought not to let his impatience show; there was no reason to be short with the guy who hadn't been obligated to stop and help in the first place, and couldn't help it that Sam was in a hurry to reach a sick friend. Sam was just relieved to have assistance in the first place.

"These cars and their computerized brains, huh?" the man asked with a shake of his head. "One zero out of place and the whole thing goes kaput." He leaned in closer, pointing to something Sam couldn't have identified if he'd tried. "Well, right there. There's your problem."

The hunter frowned, also leaning in a bit. Whatever the piece was, it was completely unfamiliar to him. Sam cast his mind back to Dean's lessons, but nothing was springing to mind. "What the hell is that?" he murmured.

"Well, that's a kill switch."

Wait a minute…

"This here is the remote," the stranger went on, still as casual and calm as could be as he held up a tiny device that he'd just pulled from his own pocket.

The implication struck like a bolt of lightning, but not as hard as the fist that struck Sam in the side of the head a second later, sending him into a dark oblivion.

SPN SPN SPN

"Sam? Sam!" Castiel's heart thudded in his chest, as he jolted up on the ramshackle bed as straight as his aching body would allow. "Sam, what's happening? Are you alright?"

The long silence that followed left the angel gripping the phone so tightly it nearly cracked. He willed his friend to speak, to prove that the strike Castiel had heard was the hunter fighting off his attacker. The angel cursed his broken wings with a low oath; if only he was whole, he could simply fly to Sam's side and help him.

But Castiel could do nothing, listening intently as the background noise shifted, a soft scraping as someone picked up the phone.

"Is this Dean?" a strange voice asked.

Castiel's heart sank. It wasn't Sam.

"Who is this?" he demanded, voice croaking slightly; he'd already used it more today than he had in the past week, speaking with Sam. "What do you want with Dean? What have you done to Sam?"

After a short pause, the stranger replied, "If you happen to talk to Dean, tell him he should give his brother a call."

"Wait, what are you going to do-" Castiel cut off as the line clicked and went dead.

The angel swore under his breath. Scrolling through his contacts as fast as he could, Castiel dialed Dean's number with his gut already clenching at the realization that he'd have to admit to Dean Winchester that he'd placed Sam in danger.

This was all his fault. Sam had only been on the road because he'd been coming to get Castiel, because of the angel's weakness. Whatever the stranger did to Sam, it was all on Castiel. How was he going to live with that? And how was he going to explain it to Dean?

"We're sorry," a voice spoke from the other end, certainly not the hunter. "You have reached a number that has been disconnected or is no longer in service."

Castiel hung up, stomach twisting even more violently. If Dean's number was no good, then the angel had no way to reach him. He knew the hunter kept several "burner phones", whatever that meant, but Castiel only had the one number on hand.

Which meant there was no one to come to Sam's aid. No one but Castiel.

The angel didn't hesitate. Throwing back the blankets, he stumbled out of the bed too quickly. The room spun, forcing him to sink to the floor and close his eyes until the wave of dizziness had passed. Though Castiel's legs didn't feel like they were fully solid, he pushed himself back up and lurched for the desk where he'd left the small computer Sam had given him.

GPS. Sam had said he'd track Castiel via the GPS in his phone if necessary. Surely Castiel could now do the same, in order to find the hunter. The Winchesters had given him a notepad with instructions for how to do this, along with some of the other more basic methods of human tracking, such as running a license plate through a police database. Besides, he'd had a little practice while attempting to find Metatron.

He could do this.

Wiping away the sheen of sweat building on his forehead at even this small amount of exertion, Castiel booted up the computer and pulled the notepad from the desk drawer. He drummed his fingers, glaring at the screen as it sluggishly came to life and connected to the motel's wireless internet.

Every moment it took was another moment that Sam was left alone in the hands of this man who clearly meant to do him—and Dean—harm. Castiel tried not to think about the sound of the man's fist hitting Sam, nor how much force it would have taken to render a Winchester unconscious. He tried not to let his mind wander to Dean, and why his phone number was disconnected, or where he might be, or why this man wanted them. Was it a demon, perhaps? A monster? Surely not an angel, though there might well be some out there who would still want revenge for the Fall.

The website finally pulled up, giving Castiel the option of turning on the GPS for Sam's phone number. Picking his cell up again, the angel fell into another violent fit of coughing as he waited for the map to load.

How could something as simple as coughing leave him so exhausted and drained? Castiel couldn't afford this, not now. Sam couldn't afford this. Choking back another fit, Castiel ran a hand over his face, then exhaled in relief when a red, blinking dot appeared on his screen.

They seemed to be moving, well over an hour away from Castiel's current position… and that was assuming he could make the drive without stopping, which wasn't likely.

Keys… he needed his keys.

Blindly groping for the set of keys on the dresser, the angel released a ragged breath as his anger turned inwards. No… he needed to focus. Castiel couldn't afford to let his self-loathing at his own failures consume him, not while Sam was in danger.

Though each step was heavier than the last, Castiel forced himself on. He was going to find his friend.