Castiel was watching Dean sleep when Sam called.

Not out of any particular interest, more for the lack of anything else to do. So he watched Dean flail out of sleep and grope for the phone, look at the screen, and groan. "It's Sam," he said, to the world at large. "Goddammit. What time is it even-"

"Late," Castiel offered. "Or perhaps early." Dean cast him a bleary eyed, annoyed look and put the phone back on the bedside table, where it continued to buzz, and finally turned off. Dean rolled back over and stuck his face in the pillow.

Only a couple seconds later, Castiel's phone began to ring from his pocket. Castiel pulled it out and looked at the number.

"It's Sam," he said, to Dean, who didn't move, merely made an inarticulate groaning sound. "If he is calling me," Castiel said, carefully, "It is probably important."

"Fuck it," Dean said, and then rolled over just enough that one eye was visible. "No, fuck him. He can deal, just this once, by himself."

Castiel looked at his phone, still ringing. "I don't think he would call me if it weren't urgent."

"Then he can leave a fucking message."

Castiel frowned at Dean for a moment. There was an uneasy feeling that he didn't particularly like and couldn't identify in the pit of his stomach. Finally, he stood up and pressed the green button. "I will take this outside," he said, finally. "I am sure it will only take a moment."

He stepped outside and put the phone to his ear. "Hello," he said, awkwardly, still not entirely sure about this contraption. He heard a shuddery breath on the other end and blinked.

"Hello," said a voice that was distinctly female and not, unless Castiel was greatly mistaken, Sam's. "Is this…um. 'Cas?'"

"This is not your phone that you are calling from," Castiel said, after a moment.

"No," said the girl on the other end. "No, it…look, my name's Lindsey, I don't know what's going on, they took him but his phone was here, and I tried speed dial one but they didn't pick up, and I don't really know what to do-"

"Took," Castiel said, and frowned. "Who took…was this Sam?"

"That's what they called him!" said the girl on the other end, Lindsey. "But that's not – he said his name was Keith and I swear those guys were crazy and they were going to kill me, they held a gun to my fucking head! They handcuffed me to a table! I was just doing my job and these guys come out of nowhere talking about the apocalypse and – look, Keith or Sam or whoever he is, he didn't seem like a bad guy, and…I dunno, you're a friend of his, right?"

Friend. That was not, Castiel thought, exactly the word he would use. Nonetheless.

"And I just – I think he could use some help. I thought…" Another one of those shuddery breaths. "I really thought they were going to kill me, and Keith just went with them and I don't think…"

"Where are you?" Castiel asked, and glanced toward the closed door, and tried to think of what questions Dean would ask. "Did you hear names?"

"—Garber," Lindsey said, "In Oklahoma, and I think – Tim and Reggie. Keith knew them. He said they were friends of his father's. What kind of – Jesus. God. Is he in Witness Protection or something-"

"Lindsey," Castiel said, making his voice sound authoritative. "It is fine. I will manage things from here, and make sure S-Keith is all right." He paused, and then added, "Please do not contact anyone else about this. It would only complicate matters."

"God," said Lindsey, after a pause that had Castiel momentarily worried. "Okay. Okay. Thank you. I don't – Jesus." A moment longer, where Castiel could hear her breathing rapidly, and then the click of a dead line. Castiel frowned at it, wondering vaguely if that was rude. He supposed she might be excused.

And then what she had been saying actually sunk in. Hunters, it sounded like. Other hunters had found Sam, and knew about the apocalypse. That was troubling. Whatever they knew, it was assuredly lacking in anything resembling nuance or real truth. Which did not, likely, bode well for Sam.

Castiel glanced over his shoulder at the closed door. He was of little use here. Dean probably did not expect him to stay.

And some small voice murmured that the apportioning of blame was not, perhaps, entirely fair. That Sam had taken on more than his share. That it was Castiel who had opened one door to make the opening of another possible.

He pushed that line of thought aside and focused on Garber, Oklahoma. It seemed that at the very least he had a duty to do, for Dean's sake if nothing else.

~.~

It was not, fortunately, very difficult to find a pair of hunters looking for solitude in a small Oklahoma town. Largely because they were the only ones who had bothered to ring themselves with a liberal application of salt.

He retrieved Sam's phone first, out of a sense of propriety, before dealing with the more unpleasant matter. The girl seemed shell-shocked and confused and full of questions that Castiel largely ignored and she didn't really seem to expect to have answered.

Castiel landed lightly outside of the circle and found a window to look through. For a few moments he couldn't see anything much at all, his eyes slower to adjust than they had been (even a week ago, so quickly everything was slipping away). When he could make out the details…he counted two men on their feet and a third, familiar, on the floor. Sam, Castiel identified, and fought the urge to sigh. He wasn't pleased to be proved right. He'd rather hoped that whatever trouble Sam had been in, he might get himself out of it.

The window was cracked and he could just hear them. For an unnerving movement, watching Sam, he looked too still, but then he stirred, if barely, pushing himself up on one hand. "I don't," Sam said weakly, turned his head and spat out a mouthful of blood. "I don't know anything. I can't help-"

One of them moved into his line of sight and all he could hear was the heavy thud of something harder than flesh striking flesh, and a small, pitiful pained noise from Sam. "Slow down, Reg," said the other one, bending down next to Sam's prone form. "He can still be useful. C'mon, now."

"I won't," Castiel heard Sam say, and then his voice was swallowed in a sound half choke, half gurgle as the first voice growled, "Don't got a whole lot of choices, Winchester."

Castiel felt a very brief surge of intense revulsion, and gave up on subtlety. It was not, after all, as though salt would keep him out. He considered the liberal application of violence, decided against it, and simply landed a few feet from Sam. The hunter who was standing only had time to blink blankly at him before Castiel dropped him to the floor unconscious. The one kneeling next to Sam stood up and turned, holding a vial stained red. Castiel could smell the dark power of it from here and his dread deepened.

The extra time didn't make the second hunter any harder to stop.

Once he was sure they were safely sprawled on the floor and would remain so for a good while, he looked to Sam.

Sam, sprawled a shuddering wreck on the floor, breathing quietly and raggedly, unmoving. Castiel felt a quick flash of pity, like fire.

This was, he thought, going to be more complicated that he'd suspected. Dean apparently wanted nothing to do with Sam, by his own rather blunt admission. Sam was clearly in need of some help, and one of the medical care facilities humans used was, he had gathered, unsafe. And there was the matter that he had apparently been given an unknown quantity of demon blood.

That did not leave him with very many options. "Sam," he said, carefully. Sam twitched minutely, one of his hands clenching, but didn't make a move to rise, or seem to recognize Castiel's voice. Castiel felt a flare of worry that perhaps he had been too late, but a moment later Sam twitched again.

"Cas," he said, voice ragged. "S'that you? How'd…" he swallowed audibly, and Castiel could see him trying to force himself up. He dropped to a crouch to stop him.

"A girl called," Castiel said, in answer to the question, trying to gauge how much physical damage there was to deal with, and if it would be safe to transport Sam out of this place via flight. "Stay still. How severely are you injured?"

Sam blinked owlishly up at Castiel, seeming puzzled. Castiel wondered idly how much of the blood on Sam's face was his own. "A…Lindsey called you?"

"She appears to have your phone in her possession, and was concerned," Castiel said. Sam appeared to be largely intact on the surface, but he knew too little about the inner workings of the human body. It wasn't something that particularly interested him, and healing had never been his strong suit.

Sam had, at least, fallen still, but Castiel suspected it was less obedience and more exhaustion. Sam looked like he was seconds away from slipping out of consciousness. "Dean," Sam said, the start of a question, and Castiel cut him off.

"No," he said, beginning to gather Sam's limbs (which seemed, at the moment, excessively long) into his arms. "It is only I. Dean preferred to sleep."

It occurred to him when Sam made a small, unhappy noise that that was probably a thoughtless thing to say. Hurtful, likely. Or perhaps it was just the last gasp of pain, because a moment later Sam was thoroughly limp and assuredly unconscious.

Castiel picked him up the rest of the way a bit less delicately and took flight to find a more suitable place to do his nursemaiding.

~.~

Ultimately, he settled on the motel for which he found the key in Sam's pocket. It was ugly and run down, but it would do for his purposes. Of course, then it turned out that Sam had very little of use in his room, only the most basic of medical kits that Castiel did not really know how to use. He sighed, giving up on being able to do anything until Sam woke up and could help, and focused on diagnostics. His ultimate total came to a nearly astonishing number of bruises, a few ribs at least cracked and probably broken, battering around the head and face that was troubling, and, of course, the matter of the demon blood. Hopefully it at least wasn't much.

Near to dawn, Dean called. "Where the fuck are you?" He snapped across the line, before Castiel could say a word.

Castiel looked at Sam, still out cold on the one bed in the room. "I am…otherwise occupied," he said, diplomatically. Dean swore.

"Doing what?"

"I should not be more than a few days."

"Cas-" Dean cut off. "Seriously. It freaks me out when you're cryptic."

"Dean…" Castiel felt a sudden surge of irritation as he glanced over at Sam. Had half a mind to tell the truth and see what Dean made of it. "I do not need to be by your side to help. Have patience. And a little faith." He hung up, and ignored the phone when it rang again. Somewhat tempted to destroy it.

He did not. Probably it would be necessary later.

He sat in the chair and watched Sam. They would need food. More medical supplies. A better, more secure place, potentially, to get Sam through the inevitable withdrawal, though where that might be Castiel had no real idea.

Why are you doing this? Some small voice murmured in the back of Castiel's mind. He is safe, and not gravely injured. He is not yours to watch over. He was a means to the end where the end is now managed, and is now more of a hindrance than anything.

It troubled him that he did not have an easy answer to his own question. Castiel almost missed the days when he had been certain. Now he only had doubts and best guesses.

Sam stirred midway through the morning. Castiel did not get up to rush to his side, waiting until Sam's eyes were fully open and Castiel could see him trying to process in the moment before the pain hit and his face tightened. "Good morning," he said, from his post. "I am not proficient with human medicine and require your advice." Sam stilled at once.

"Cas," he said, after a moment, not quite turning to look at him. "You're…really here?"

"Yes," Castiel affirmed. "My apologies that I could not do more before you awoke. I was never much of a healer, and it does not appear that you have many supplies."

Sam turned his head and blinked sluggishly. He looked dazed and a little bit lost. "Why're you here? S'posed to be with…"

It's a good question, that same voice from earlier commented, and Castiel pushed it down. "Is that relevant?" Sam seemed to be seriously considering that question and coming up blank, so Castiel moved away from it. "What supplies do I require to tend to your injuries?"

There was a flicker of an expression Castiel didn't understand across Sam's face. "It's not that bad. I can-"

"Do you intend to deal with the withdrawal by yourself as well?" Castiel said, hazarding a guess but keeping his tone flat, and Sam flinched violently, eyes skidding away from Castiel's. Castiel almost felt poorly about bringing it up. So he'd been right, it was probably more than he'd seen, and Sam did know.

"I can," Sam started to say, and Castiel cut him off with a sharp, "You would only be a danger to yourself and others. I do not mind."

Sam seemed to shrink into himself and didn't respond. Castiel frowned. "Ice," he said, finally. "Bandages. Some painkillers if I'm out, the generic stuff is fine. I'm sorry. I should call Lindsey and…" Sam trailed off. His color, Castiel noticed, had gone from bad to worse, and his eyes seemed to be sliding vaguely out of focus. That probably did not bode well. Guessing at the end of that sentence, Castiel tried to sound comforting.

"I will ensure she knows that you are safe, and will return shortly. I do not think continuing to rest would go amiss. You do not look well."

Thinking of Dean, he didn't give Sam a chance to argue, simply took flight to find the nearest place with access to the supplies Sam had mentioned.

~.~

He came back with more than he believed would be necessary to what appeared at first sight to be an alarmingly empty room with scattered patches of blood on the floor. Then he heard retching from the bathroom and sighed. Quietly, and to himself.

It occurred to him to wonder if Winchesters were wholly incapable of following instruction or only ignored it when it was bad for their personal well being to do so.

He opened the door and found Sam with his head hanging over the toilet, panting but appearing to be finished. For a moment, Castiel thought his arrival hadn't been noticed, and then Sam made a small noise and said, "Think I might have a concussion. Um. Sorry."

"I do not know what for," Castiel said, after a moment. "You appear to be a great deal more miserable than I am."

The look Sam gave him was decidedly perplexed.

"Can you get to your feet?"

"Mmm," Sam said, noncomittally, and squeezed his eyes closed, and then winced. What had looked like relatively mild bruising an hour ago now appeared a great deal more severe. Castiel felt a mild, detached sort of distaste. He had not observed Sam fighting back. There seemed to be no real reason to have dealt so severely with him.

"Perhaps," Castiel started to offer, but Sam shook his head, and then looked like he was seriously considering vomiting again.

"—no. Sorry, that's not – sorry. Just give me a second."

Castiel severely doubted that a second would be sufficient, but decided that it would probably be polite to let Sam try. He waited in the doorway and watched Sam struggle with trying to get up, fingers clenching white knuckled on the counter as he hauled himself halfway there and then had to stop, panting.

Finally, he ventured over and pulled Sam the rest of the way up. "I believe this will be easier if you allow me to assist you," Castiel said mildly, and Sam flinched again, like he'd been chastised. He avoided Castiel's eyes.

"Sorry," he said, swaying slightly. Castiel didn't let go, suspecting Sam would probably end up back on the floor if he did.

"As I said," Castiel said mildly. "I do not mind. I do not think either of us wants this to be harder than it has to."

"Yeah," Sam said, after a moment. "Um." He looked like he was trying to focus. Making a guess, Castiel started to move them both in the direction of the bed. Sam looked like he was dangerously close to slipping back into unconsciousness, which would be inconvenient.

"What did those men want from you?" he settled on asking. Sam made a faint, unintelligible noise.

"Not sure," he said, after a moment. "Something between siccing me on demons and beating the crap out of me for shits and giggles, I guess."

Castiel frowned, took a moment to ponder what 'shits and giggles' were, and gave up on it. "I see," he said. "How much blood did you consume?"

Castiel thought he had done an admirable job at keeping his tone non-judgmental and even. Sam still jerked like he'd been slapped, stumbled slightly, almost falling into Castiel. "I didn't want," Sam said, sounding almost breathless, then paused and tried again. "I tried to-"

"It was a simple question," Castiel said evenly. "I am merely trying to gauge what I should expect."

Sam's body did another of those twitches. "Not…not much. I can't…can barely even…just enough to take the edge off wanting…" Castiel could see Sam's face scrunch up in shame and felt an abrupt and confusing burst of sympathy. Sam had made this choice, he reminded himself. Gotten himself into this situation, this addiction.

All humans sin by choice. A different voice, this time. And through grace they are forgiven. Castiel sighed.

"It will be well," he said. "Likely not as bad as it was previously. I will do what I can to make it easier." He let go of Sam when he was sure the younger Winchester could make it to the bed, and went to fetch the supplies he had – co-opted. When he turned, he found Sam staring at him, eyebrows furrowed.

"Why are you here, Cas?"

The question had been asked before, but Castiel did not think Sam had forgotten. Rather, he suspected the answer previously given had been unsatisfying. "You required assistance," he settled on, though it did not feel entirely accurate. "I was unoccupied."

Sam made a soft chuffing sound. "Nothing better to do?"

"Not particularly," Castiel said, without thinking about it, and then got a look from Sam that looked curiously hurt. He went back over what he'd said and frowned. "That is not exactly…"

"It's fine."

"It is not a matter of," Castiel started to say, but Sam jerked his head and said "It's fine," more insistently, which it clearly was not but Castiel suspected that pointing that out would not get him anywhere. "Very well," he said, reluctantly. "Now. How is this equipment to be used?"

~.~

Sam tried very hard to downplay the severity of his injuries. Perhaps they were not life-threatening, that much was true, but Castiel was neither experienced nor gentle and Sam could not entirely prevent the reflexive flinches whenever Castiel's fingers brushed across the large bruises carpeting his body. Castiel quickly came to his own conclusions, which were 'worse than previously believed.'

Sam had not been bleeding much outwardly, but Castiel still felt the need to wash his hands after Sam had curled up and gone back to sleep. Or passed out; it was difficult for him to say which. It struck him all over again as he emerged and looked at Sam on the bed, mouth set in s amll frown, how fragile and breakable humans were.

And that Sam was, still.

Human, that was. Vulnerable. Breakable.

Sam, Castiel thought, was interesting. Quiet and self-conscious in Castiel's presence, with that dark undercurrent burning through him that Castiel could not ignore. If Dean was a cipher, Sam was doubly so. Castiel did not desire more uncertainty in his life, but there was a part of him that wanted very much to understand.

Castiel sat down on a chair in the room and laid his hands on his knees. A brief, dark thought flickered across his mind and he dismissed it in the next moment as pointless. Or worse.

Sam twitched in his sleep and started to shiver. Likely the withdrawal would begin soon, which would be unpleasant, but Castiel hoped they would not need to move. After a moment more considering the younger Winchester and his restless state, he stood up and stepped outside to call Dean. It was midafternoon. Hopefully he would not be occupied.

(He felt almost proud of his growing proficiency with the device.)

"Cas," said Dean before he could get a word in edgewise, voice almost a growl. "Ready to tell me what's going on?"

"No," said Castiel evenly. "Merely assuring myself that you are still well. Are you?"

There was silence for a moment. "…I'm okay, yeah. Listen, did…is this about something Sam said?"

Castiel considered that. It was not, really. "No," he said. He heard Dean breathe out sharply.

"What did he say to you, anyway?"

"Very little," Castiel answered honestly, and then added, cautiously, "He merely passed on some information."

"What information?"

"Nothing of import." Castiel glanced back at the door, and felt a brief twinge of something like worry. Despite Sam's insistence, he was not sure himself that there was no lingering invisible damage. "I should probably go."

"Jesus, Cas," Dean said. "You with a girl or something?" Castiel was almost, almost amused.

"Or something," he said, and hung up.

He ventured back in to the motel room and found Sam twisted up in the blankets and shivering violently. He walked over and held out a hand, and could feel the heat rising almost an inch from his skin. Touching Sam's face bordered on uncomfortable, and he didn't wake at the contact, merely shuddered.

Withdrawal, he thought. It'd come on faster than he'd expected. Probably the vomiting earlier had expelled some amount of it from his system. "For what it's worth," he informed Sam, who couldn't hear him. "I am…sorry that this has happened to you." He didn't know why he said it. It was not, after all, like Sam could hear him.

Perhaps saying it aloud when Sam could would have felt like too much of an admission of his own culpability. Perhaps that was his discomfort with Sam. Perhaps it had nothing to do with Sam himself at all.

Castiel did not enjoy that line of thought.

He pulled a chair up next to the bed and sat down to wait.

~.~

Castiel wasn't sure what he expected. His experience with drugs, after all, was miminal to say the least, and demon blood was not exactly a typical substance. He hadn't been present for the majority of the last time Sam had gone through this, so he had no idea how relatively bad that had been.

Except that he had asked, once, about timing, and Zachariah and glanced at him almost scathingly and said, "Just don't wait too long or there's a chance his heart will give out."

Castiel knew there was no real risk of Sam dying a final death when Lucifer still required his participation, but it was nonetheless a grim prospect. He hoped that it didn't come to that.

Sam began to scream a few hours in. Castiel had enough strength to put up a weak shield around the room suggesting that the people adjacent and walking by ignore the sound, though he would not be surprised if it did not turn out to be enough. Sam's whole body arched with it, howling, agonized screams that didn't abate until Sam was gasping, simply unable to pull in enough air to scream any more.

Castiel moved from his chair to lean across the bed and pin Sam's shoulders down. Sam's body twisted against his, thrashing jerkily, seeming to find new strength. His eyes snapped open, rolling wildly before they fixed. "Dean, please," he said, looking straight at Castiel but not seeing him. "Please, I didn't – I never – stop please stop stop oh god-"

His voice rose into another howl like he was being ripped apart. His body felt scorchingly hot where it touched Castiel's. Surely something needed to be done about that. He needed to know what.

"Sam," he said, trying to make his voice firm. "Listen to me. Focus on me." Sam's whole body went taut and then slack, and his screaming faded to panting, desperate gulps of air. Heartened, Castiel started to continue, "I think you must-"

"No," Sam said raggedly, right over Castiel. "Oh god. Please. Dean, I didn't mean to. I didn't mean to. I know you don't trust me but – just one more chance, please, give me another-"

Back to wordless screaming. Castiel sighed and lapsed into silence before rising to dampen a cloth and lay it on Sam's forehead as he had seen someone do on one of the programs Dean seemed to like to watch.

It occurred to Castiel that he had last heard screams like the sounds Sam was making in Hell, from damned souls being pulled apart.

Sam's whole body bucked against Castiel's grip, his hands lifting to scrabble at Castiel's wrists. His back bent like a bow, cramps straining his muscles to the breaking point. The screams died and Sam was gasping like a fish thrown onto land, desperately sucking air.

Castiel lowered his head and began to pray aloud. Sam went limp and dropped back to the mattress, twitching. "Sorry," Castiel caught him saying as his head twisted back and forth and finally stilled, his chest heaving. "I'm sorry. Cas. I'm sorry. Oh god. Please just-"

Five hours in, in a brief break where Castiel was not keeping Sam from breaking his own body in two, he got some water and brought it back, put it to Sam's lips. Sam turned his head away. "Won't," he said, voice cracked and ragged from the screaming. "Won't drink it, you can't-"

"It is only water," Castiel said, trying to be coaxing, and managed to dribble a little into Sam's mouth. He swallowed greedily, and then grabbed for the glass and guzzled the rest.

Only moments later, it came back up as sour smelling clear liquid, and Sam curled into himself, clutching his ribs and making awful, wet sounds somewhere between dry heaving and sobbing. Castiel looked at him and felt a rush of bitterness.

This was not his duty. This was not his assignment.

(And yet…if he had not come. What then? Or if he had left Sam to face this alone…)

Abruptly, and rather to his own surprise, Castiel felt a surge of frustration with Dean. Dean, whose loyalty and courage and determination to spite destiny had been the reason for Castiel to disobey, because he looked at Dean and admired his choices. Sam shaped you as much as you shaped Sam, Castiel thought. You can't simply deny that, and then wondered why he was thinking to defend this man.

"Sam," he said, keeping his voice quiet. "Try again. More slowly."

Sam made a pathetic choking sound like he wanted nothing less. But he accepted the water. Drank a little, more slowly, shaking so hard that Castiel didn't even let him attempt to hold the cup. "I'm sorry," Sam whispered again.

As am I, Castiel thought. He considered speaking it aloud. "Let yourself rest," he said instead. "It will be over soon." For how long, he wondered, and did not know. If it took days, food would become a problem. He should have thought to ask Sam for details in this.

The dark thought crept into Castiel's head that perhaps Sam had never meant to survive this ordeal. It sent an unexpected shiver down his spine. He frowned down at Sam, who looked back at him, eyes apparently clear.

"Cas," he said, hoarsely, "Take the knife. Take it and carve the dark out of me. Please. I just want to be good. I just want…"

Is this what Heaven and Hell made of you? Castiel thought. The cloth on Sam's forehead was nearly dry. Or is this what you made of yourself? Does it even matter?

God values forgiveness, and compassion. Who are you to do less? Who are you to judge worthy and unworthy?

"Please," Sam said, voice verging on desperation. One arm wrapped over his wounded ribs as he struggled to sit up further. "Please, I need-"

It is not love in spite of the imperfections, but because of.

He caught Sam's hand reaching for him and eased the younger Winchester back down. "Sam," he said softly. "It is well. I will take care of you."

~.~

Castiel found himself wishing that there was more he could do. It seemed so pathetically little, what he could. Barely enough to keep Sam even marginally comfortable during his few moments of lucidity.

The withdrawal seemed to go through a cycle: pain that corkscrewed Sam into screaming knots until he was too exhausted to move and just lay limply, staring blankly up at the ceiling. Then hallucinations, vivid and violent and from what Castiel could tell, nearly always starring Dean.

Listening to Sam talk to his hallucinations was a little uncomfortably like reading his mind. At first Castiel tried to shut it out, or ground Sam in reality, but in the worst moments his voice hardly seemed to reach Sam at all. So he listened.

Listened to Sam confront his brother over and over again, plead for his life, his innocence. Admit his own faults and mistakes in painstaking detail.

And when the hallucinations faded, Sam would slip into unconsciousness, for an hour at most.

And then again.

Once, only once, he caught the whisper of the demon's name, and couldn't tell if it was said with hatred or longing.

Castiel coaxed water into Sam when he could. Attempted to keep the cool cloth on his forehead though it seemed largely ineffectual in moderating the temperature burning through Sam's body. That was about all it seemed he could do. And watch. Witness.

It took a day and a night for the symptoms to ease. Even after Sam finally quieted for good and slipped into what seemed like sleep rather than unconsciousness, he was still trembling violently, and the air smelled faintly like sulfur. Castiel felt weary as he seldom did.

He checked his phone. Dean had called three times since their last contact.

Castiel did not call him back.

~.~

Sam stumbled into the shower the moment he woke up and emerged both looking and smelling somewhat more human. He did not look directly at Castiel as he moved around the room, stripping the bed soaked in his sweat and other…things, still limping and moving gingerly.

Castiel contributed by finding a can of soup in Sam's supplies and making it by carefully following the directions on the label. He proferred the bowl when Sam paused for a moment, and he took it after a second's pause and sat down on the bare mattress. Castiel could see his hands trembling slightly. He seemed to be thinking.

"Thank you," Sam said, after a moment. "For…" he trailed off.

"I did little enough," Castiel said honestly. Sam's eyes flicked briefly up and then back down.

"Still," he said. "Thanks."

They sat in silence for a few moments. Sam stirred his soup, picked up a spoonful and blew on it, then let the liquid fall back into the bowl.

"Did you know about me?" Sam asked, quietly. His voice was hoarse and he was picking at the soup disinterestedly. Castiel frowned at him.

"I'm afraid you will have to be less vague."

"Did you know that I'm Lucifer's vessel?"

Ah. Well that answered that question. "Yes," said Castiel. "I knew in the event of the apocalypse that that would be your expected role."

"Huh," said Sam. He made a small sound that was almost amused. "Guess that makes sense." He paused, and looked at Castiel for the first time, eyes dull. "He said that he won't let me die."

"Yes," Castiel said. "Given your connection, it would not be difficult."

Sam twitched and looked down at his hands in his lap for a long time. Then he said, very quietly, "Could you override that?"

Castiel blinked, surprised, and took a moment to attempt to understand what was being asked of him, and then another moment to try to comprehend why. "I don't know," he said honestly, before he had worked out the latter, and then thought a little more about it and frowned. "Are you requesting my assistance in your suicide?"

Sam winced. "Yeah," he said, after a moment. "I guess I am." His voice was very calm. It didn't strike Castiel as normal. He tilted his head to the side.

"Life is the greatest gift given to creation."

"And free will." There was something intense, suddenly, about Sam's gaze on his. "So if I choose…"

"How would your death be in any way productive?" Castiel asked, perhaps more sharply than his adopted position of strict neutrality warranted, but the more he thought about it the more unpleasant the idea of killing Sam Winchester became. He didn't want to. And not merely for the purity of his own conscience, because critically, he did not think that Heaven could look poorly on killing Lucifer's chosen vessel.

Sam straightened, like he'd been waiting for that question. "I can't say yes if I'm dead, can I?"

Castiel frowned. "I am not…certain."

"Even if I can," Sam said, implacably, "I wouldn't be a knife that could be held to Dean's throat, at least, and I figure I could buy myself a little time if I refused to go with the reaper and stuck around here. So if you overrode Lucifer's 'no dead Sam' deal, then I could effectively be out of the fight and at least the Devil would be down on that front. He's weaker in this other vessel, right? So there's more of a chance-"

It took Castiel a moment to pin down the sensation he was feeling as nausea. "No," he said, roughly, cutting off the end of Sam's sentence.

Sam looked genuinely startled. And then frowned. "If this is…I mean, if you have a problem with getting blood on your hands, or whatever, you don't actually have to…you know. Just make it so he can't bring me back and-"

"No," Castiel said again, a bit more loudly. Sam blinked at him, apparently bewildered.

"Why?" he said. "Strategically, it only makes sense, and I mean, I guess Dean might be a little upset, but he'd-" Sam swallowed, once, and Castiel saw a flicker of something, very briefly, before it was gone. "—he'd get over it."

"Regardless of…I do not think this is a good plan," Castiel said, keeping his voice deliberately level.

"—why?" Sam asked, genuinely perplexed, and Castiel felt – something. He wasn't sure what. Between sympathy and pity. He remembered the Sam he had first met, proud and sure no matter how wrong he was. Set beside this man…

It was difficult not to feel like he had erred, somewhere. Castiel did not enjoy destruction, and that was what this looked like.

"I do not believe it would be advantageous," he said, after a moment of struggling not to say I don't want to, I have abruptly discovered that I have a somewhat personal interest in your survival.

"But if I say yes to Lucifer-"

"Do you plan to?" Castiel asked, and Sam stared at him, appalled.

"No! Of course – of course I don't plan to, but things don't always go the way I plan and I don't have the best track record on things right now-"

"Then you will not," Castiel said, in what he thought was a very reasonable voice. Sam stared at him like he'd grown an extra head.

"What?"

"If you do not intend to say yes, then you will not." Castiel folded his hands in front of himself. "It is that simple."

Sam was shaking his head. "No, it's-"

"Do you doubt me?" Castiel asked, placing just the right amount of sharpness in his voice, and Sam did not quite flinch.

"No," Sam said quickly. "I just…" he trailed off. "…seems like the choices I make never go the way they're supposed to. Somehow it always…"

Castiel spoke slowly, carefully. "If the past year…if Dean has taught me anything, it is that…humans are somewhat greater than the sum of their destiny. You are more than I would have expected. I do not doubt that you will confound the expectations of others as well."

He turned his eyes away from Sam because it almost hurt to look at the way Sam gazed at him, somewhere between confused and awed and hopeful. "I will not do this thing you request," he said. "It would be wasteful. You erred, yes, gravely. I do not believe you will do so again."

Sam half opened his mouth, and then closed it. "I'm sorry," he said after a moment. "I don't mean to…"

"I confess," Castiel said, interrupting, "That I am not certain what you continue to apologize for. You have not offended me."

~.~

Sam fell asleep not long afterwards. He had eaten very little of the soup, Castiel noticed with worry. Perhaps he could endeavor to ensure that Sam consumed more when he awoke again.

His phone was ringing again. With a sigh, Castiel exited the room and picked it up. "Yes?"

"Jesus Christ!" Dean said, over the line. "Where the Hell have you been?"

"I told you. Otherwise occupied." Castiel wished briefly that he had left the curtains open so he could keep an eye on Sam. "Why are you calling me?"

"Can you get back here?"

"Not this instant. Soon."

"Fucking-" Dean cut off. Castiel could almost hear him trying to calm himself. "Look," he said. "I heard something through the grapevine about Sam and I just – he's not picking up his phone and I…"

Castiel waited, acutely aware of Sam's phone in his own pocket, thoroughly ignored and almost certainly out of battery.

"I'm worried, all right?" Dean said, sounding more irritated than concerned to Castiel's ears. "Apparently some hunters tracked him down, and I just…"

"Do you expect that hunters would harm your brother?" Castiel said mildly. There was a brief silence.

"Maybe not, it's just…Sam always picks up his phone. And…look, anyway, you talked to him, right? Did he give you any idea of where he was?" And there, rather abruptly, Castiel could hear the worry, and felt a petty (perhaps) surge of slight satisfaction.

"We did not discuss it."

"Cas…"

"I will return before too long, Dean," Castiel said. "And then we may seek your brother, if you wish."

"It's not that I wish," Dean said, the momentary trace of worry evaporating in a hurry. "Someone's got to keep an eye on him."

Castiel hung up so he did not inform Dean rather sharply that someone was.

He re-entered the room and found Sam awake again, staring at the ceiling. "You did not sleep for very long," he said, carefully. Sam's eyes drifted half closed.

"Yeah," he said. "Well. Lucifer keeps…you know. Almost like detox was a break." He made a small, hoarse sound in the back of his throat. "Anyway. I guess you'll be…going back to Dean now."

"It seems I must," Castiel agreed. "Yes." He sat down at the table and regarded Sam. He had a feeling there was more that the younger Winchester wanted to say.

Sam's shoulders drooped downward slightly. "You'll…look after him, right? Not that – I mean, I know you will, that's what – Jesus. Sorry."

"You apologize a great deal," Castiel commented, instead of addressing anything else. Sam shrugged one shoulder and one corner of his mouth turned up in a bitter half-smile.

"Kind of got a lot to apologize for, don't I? Made the mother of all mistakes." Sam's hands twisted together in a way that looked painful.

Castiel frowned. "I erred as well," he said, surprising himself, and apparently Sam as well. "To cite only one instance – I failed to recognize Uriel's treachery and thus subjected your brother to unnecessary pain at Alastair's hands."

Sam's expression flickered. "You can't expect yourself to know everything-"

"But to not recognize a brother's betrayal?" Castiel said, and then wondered if that had perhaps been the wrong thing to say when Sam flinched and curled into himself in a way that looked like it hurt.

"Maybe especially then."

"Sam," Castiel said, trying to make his voice stern. "I do not believe your part in this is over."

"Yeah," Sam said, his voice thick with bitterness, "I know, I still have to let the devil possess me so he can-"

"That is not," Castiel said somewhat irritably, "What I meant. I do not believe that this separation between you and your brother is permanent. He will need your assistance."

"He has you," Sam said, and the tone of his voice was simultaneously protest and pleading, his eyes skidding down to the floor, away from Castiel. "Isn't that…I'm just the boy with the demon blood," Sam said, heavily, like he was repeating something he'd been told many times over, and Castiel supposed he was. He wished, momentarily…but the past could not be changed so easily. Only what actions he took from here forward.

"And I am a fallen angel," Castiel said, and deliberately kept his voice level, did not let himself feel the pang voicing it caused. "There is a verse, is there not, in your Bible? 'He who has not sinned may cast the first stone.'"

For the first time, Castiel felt unworthy of the confused awe in Sam's eyes. Felt the urge to admit… You are a curious human being, Sam Winchester. I hope that I have done something of worth here.

You fell for Dean, but Sam can teach you how to be human.

It was a strange thought, and one he did not fully understand. Castiel filed it away to ponder later. "Cas," Sam said, quietly.

"Sam," Castiel said, quietly. Sam looked up at him. He looked exhausted. Hollow-eyed. "I think," Castiel said slowly, "That your brother is wrong about you. You're stronger than you know."

He took flight.