A crashing sound from the hallway shattered the stillness that had fallen over Sam and Cas. Cas flinched violently against Sam's chest, and Sam instinctively tightened his arms around him, shushing him gently – even as his heart sank. There was only one person who could have made that sound – and Sam had no idea how much Dean might have heard.

"It's okay, just… let me go see what happened, all right?"

Sam gently pushed Cas back a little, running a hand through his hair before tilting his head up to look at him. Cas looked like he was going to be sick, his eyes moving between Sam's face and the open doorway before he lowered his head into his hands.

"He heard. Sam, he heard everything…"

"Maybe not," Sam muttered, getting to his feet. "Cas, just wait here, okay? I'm gonna catch up with him and make sure he's all right, and I'll be back. All right?"

Cas nodded, looking up at Sam as he clutched the blanket tighter around himself. Sam hated to leave him, but it was a matter of prioritizing risks at the moment; if Dean really had just heard their entire conversation and found out what Sam had just discovered – then Dean was definitely the highest priority at the moment.

"Dean?" Sam called out as he stepped out into the hall, looking both ways and seeing no sign of his brother – just the cabinet in the hall slightly shifted from its usual position. "Dean!" Sam yelled his brother's name as he took off at a run toward the stairs. "Dean, come on! Where are you?"

He took the stairs several at a time, calling for Dean, and receiving no response. With a sinking feeling in his stomach, Sam took the next set of stairs up to the main door, opening it and stepping out into the bright afternoon sunlight. It took his eyes a moment to adjust – and then he saw what he'd been afraid he'd see.

The Impala was gone.

"Damn it!" Sam hissed as he stepped back into the bunker and closed the door, already reaching for his cell phone with his other hand.

As he descended the stairs and returned to the library, he listened to Dean's phone ringing on the other end of the line – with no response, as he'd expected. He glanced up and noted with surprise that Cas was standing in the doorway across from him, watching Sam with an anxious expression on his face, the blanket still wrapped around him. As Dean's voicemail picked up, Sam closed his eyes, drawing in a deep, steadying breath – grateful that he'd seen Cas standing there before he started to speak.

"Dean," he began, choosing his words carefully. "I'm… not quite sure what you heard, but… we need to talk about it. You need to come home, right now. Okay? Or… at least pick up your phone. Call me back."

He disconnected the call, and then immediately dialed again – with the same result. With a shaky sigh, Sam sat down in the nearest chair, resting his elbows on the table and his head in his hands. When he thought of Dean standing in the hallway, overhearing everything that Cas had said – he felt sick.

As if he didn't already feel shitty enough about it… and he had to find out in the worst possible way…

A soft touch on his shoulder startled Sam out of his thoughts, and he jumped a little, looking up to see Cas standing beside him. Cas immediately withdrew his hand, slowly sitting down in the chair next to Sam's.

"You should go after him," Cas said quietly, his eyes averted, his expression unreadable. "He needs you."

"I know," Sam sighed. "But, how? He took the Impala, and we're five miles from the nearest civilization. By the time I get to anywhere I can get a car, who knows where he'll be? I don't even know what direction he went."

"I would imagine he'll be heading in the direction of the nearest establishment that sells alcohol," Cas suggested with an apologetic little grimace, glancing up to meet Sam's eyes for a moment before looking away again with a heavy sigh. His tone suggested he was confessing to some embarrassing flaw when he continued, "At least I hope that's where he's going. I – I'm experiencing a surprising level of concern for his safety."

Sam felt a rush of affection for the confused angel, and he reached out to rest his hand over Cas's on the table. "Yeah, me too, Cas," he sighed. "Me too."

It was all terribly confusing.

On some level, Castiel felt relief just to know that Dean wasn't in the same building with him at the moment. But at the same time, an uneasy sensation was settled in the pit of his stomach – a pull of responsibility, of concern as familiar as breathing – an awareness screaming out inside him, the awareness that Dean Winchester was in danger, and he had to do something.

But… there was nothing he could do.

And there was nothing Sam could do, either.

Sam took out his phone for the fourth time, rising to his feet again and resuming his pacing as he dialed Dean's number again. He waited a few moments, then spoke – and his voice was taut and sharp, like a frayed rope a fraction from snapping.

"Dean. You need to call me. I need to know – I don't care where you went, all right? I just have to know you're…" His voice broke off, and he was quiet for a long moment, before continuing in a lowered voice that Castiel was fairly certain was intended to prevent him from making out what was said. But apparently his grace was gradually replenishing itself, because he could clearly hear ever word. "I just need to know you aren't going to just go… drive the Impala off a cliff somewhere or something. Just – Dean – please."

Sam disconnected the call, raising a hand to cover his eyes and swearing under his breath as he dropped his phone onto the table with a little more force than was strictly necessary.

Castiel bit his lip, frowning, feeling restless, helpless. A few days earlier, he could have located Dean in a matter of moments. Now, he was sitting here with his broken, useless wings on full display, some secret, shameful part of him relieved that they wouldn't carry him to wherever Dean was – and feeling terribly guilty for that relief.

He couldn't wait for his grace to come back at full power, and free him from the confusing, overwhelming tumult of human emotions.

Castiel approached Sam cautiously, reaching out a hand to touch Sam's arm, and Sam lowered his hand from his face with a heavy sigh.

"I wish I could take you to him," Castiel said softly, and for all his apprehension, it wasn't a lie. "I'm…"

"Don't you dare."

Sam's voice was low and firm, and he looked up to meet Castiel's eyes, something fierce and commanding in his tearful gaze. Castiel blinked, startled at Sam's reaction. His mouth went dry, and he went immediately, obediently silent. The guilty feeling intensified, and he wondered if Sam had somehow sensed his conflicting feelings when it came to Dean, and his current absence in the bunker.

But then, Sam's eyes softened, his mouth trembling as he let out a shaky breath. His shoulders fell and he reached out a hand to rest on Castiel's shoulder, his voice much softer as he explained.

"Just… you shouldn't be apologizing for – for the fact that your wings don't work right now, Cas." Sam let out a brittle, breathless little laugh, shaking his head. "There is just – nothing that is right about that."

Castiel understood, then, and reminded Sam quietly, "It's not your fault, either."

Sam closed his eyes, his mouth drawn taut and tense, and Castiel backed off a step, feeling somehow incredibly small, and obnoxiously intrusive at the same time. Sam looked up, his eyes locking onto Castiel's, and there was something unreadable there, some strange intensity that Castiel didn't have the human experience to name.

"Cas…" Sam began, then hesitated, a slow swallow visible in his throat.

Castiel was on the verge of apologizing again, though he wasn't sure what for, when Sam's phone vibrated on the table. Sam snatched it up and looked at the screen – then let out a heavy sigh, visibly relieved, as he sank down into the nearest chair again.

" 'I won't. I promise. Back later,' " he read aloud, before looking up at Castiel with a weak, faltering smile, relief and sorrow mingled in his eyes. "Well. I guess that's the best we're getting for now."

Castiel sat down slowly beside Sam again, vaguely surprised at the level of relief he felt. "It's something," he acknowledged quietly.

"Yeah," Sam agreed, looking down at his phone and letting out a heavy sigh as he set it down on the table. "And – I don't have a car, so – I guess we have to take what we can get, and – and wait for him to come home." Sam was quiet for a moment, before he glanced around at the messy stacks of books and papers Dean had left on the table. "Well," he began after a moment, "I guess we could try to make good use of the time – see if we can figure out where he left off, and… and maybe find the solution for your wings."

Sam looked expectantly up at Castiel with a smile that was a little too bright – and Castiel couldn't miss the weariness around his eyes, the slump of his shoulders. A fresh pang of guilt went through him as he realized for the first time something that he was fairly certain had already been true for quite a while.

Sam was exhausted.

Looking after me, and looking after Dean, and worrying about one every time he's with the other… how is he still functioning at all?

"Thank you, Sam, but we don't have to do that right now," Castiel suggested. "This would be a good time for you to get some rest."

Sam's smile softened, and there was warmth and appreciation in his eyes as he reached out to cover Castiel's hand with his own. "I couldn't sleep," he pointed out. "Not until I know for sure he's okay. Besides, I like research. It'll make the time go faster."

Castiel tried again. "Sam, you look terrible. You need sleep…"

"Thanks, Cas," Sam chuckled, his voice low and weary. "But I'll sleep when Dean's home safe. I promise. Just… let's try to get something done while we wait."

It was quickly apparent that Sam was not to be dissuaded from his chosen course of action, so Castiel gave up and opened one of the books Dean had chosen to the place he had marked.

It was also quickly apparent that if Dean was looking for a spell to hide Castiel's wings, he was looking in the wrong places. There were notes taken down in the margins of the book, marking rituals with similar aspects to the "Unspeakable" ritual he'd already performed, along with notes on certain spell ingredients and what their properties were. The more Castiel found, the more uneasy he began to feel, as things slowly became clear. It seemed Dean had become impatient, and was now pursuing an entirely different course of study. Castiel let the book in his hands drop the couple of inches to the table, looking up across it at Sam, feeling sick. Sam looked up, a frown creasing his brow.

"I don't think Dean's looking for a spell anymore," Castiel explained quietly. "I think he's… attempting to design one himself."

Sam's eyes widened as he took that in, his frown deepening. "Oh," he replied at last, his voice carefully even. "Well, that's… that's just…"

"Terrifying," Castiel whispered, the word escaping his lips before he could stop it. Sam froze, his expression stricken, and Castiel's heart sank. "No, no," he hurried to clarify. "I don't mean… not because of what he…" He stopped, willing down the wave of nausea that had risen in his throat, drawing in a shaking breath and struggling to calm his racing heart. Finally, he tried again, slow, carefully choosing his words. "I don't believe that Dean intends to harm me. Nothing like that. It's just – working magic is dangerous enough. Composing it… especially when one is… inexperienced at doing so…"

"Yeah," Sam agreed, sighing, his shoulders relaxing a little as he understood. "It's… not a good idea. We'll – I'll talk to him when he gets back. And – sobers up." He grimaced, apologetic.

"Why would he even consider something so reckless?" Castiel murmured, frowning down at the book in front of him. The churning in his stomach was intensifying, and his hands were damp and cold. He tried to swallow down the rising panic he felt, but he heard it in his own voice. "Dean of all people should know by now the danger of magic. He's always been particularly cautious about its use. So why would he…?"

"He's desperate." Sam's voice was quiet, but somehow arresting, silencing Castiel's musings and settling an ache deep in Castiel's chest. "He… wants so badly to fix things that… he's willing to try anything at this point. Even something as reckless as…" His voice trailed off, and he shook his head. He looked up at Castiel, forcing a smile. "But we won't let him. I'll make sure he knows that's a bad idea, we'll find another way…"

Sam was still talking when Castiel pushed back his chair abruptly, rising to his feet. Sam frowned.

"Cas?"

Castiel closed his eyes, trying to shut it all out – the hammering in his chest, the queasy feeling in his stomach, the confusing, distressing feelings that overwhelmed him at the thought of Dean's desperation to help him, to undo… what he'd done – all in combination with the constant, hovering presence in the back of his mind… the memories of what had happened in that dark basement room. Sam's soft words, explaining and defending Dean's perspective in all of this – it was too much, and suddenly Castiel felt trapped and claustrophobic.

If he'd had the use of his wings – he'd have been halfway around the world by now.

"Cas?" Sam repeated, one hand braced on the table, about to stand, about to approach him and hover and touch him and ask all kinds of agonizingly concerned, cautious questions. "What…?"

"I'm all right," Castiel insisted, holding up a hand to hold off the gentle onslaught. "I am, I just – I need to take a walk. To – to think. Alone. Please," he added as an afterthought.

Sam hesitated, visibly doubtful. "I've gotta say, Cas, if you're both out there, who knows where, and me stuck in here worrying, I think I'll…"

"I won't leave the bunker," Castiel promised quietly, offering Sam a reassuring smile, though he couldn't quite meet Sam's eyes. "I can't, really, with – my wings like…" His voice trailed off, his face flushing hot with embarrassment, and he cleared his throat, struggling to find some explanation that would convince Sam to let him go, and to make his words come out in something resembling a normal tone. "I just… it's time I explored this place further, isn't it? Learn my way around?"

Sam remained silent, so Castiel forced his eyes up to Sam's face, still smiling, hoping to put Sam at ease.

"My grace is returning, a little at a time. I still have an excellent sense of direction." At Sam's raised eyebrow, Castiel looked away, once again embarrassed as he thought of their conversation earlier in the computer room. He clarified, feeling awkward and self-conscious, "At least… when I'm not fleeing in panic."

Sam let out a soft laugh, finally, and Castiel knew before he spoke that he was relenting. "All right. I'll stay here and see what I can find out, and you just… take your time. I'll be right here if you need anything."

"Thank you, Sam," Castiel replied with genuine gratitude, before heading down the hall nearest to him, away from the library as quickly as he could.

It was just incredibly overwhelming – the weight of Sam's constant concern, and the feeling that he was letting Sam down every time he showed his fear, or anger, or uncertainty about his current situation; the confusion of seeing the evidence of Dean's research, Dean's attempts to somehow make up for the unspeakable damage he'd done to Castiel's body, to his grace, to his very being; the strange anger he felt at that knowledge – swiftly followed by guilt for being angry, because Dean was trying to help, wasn't he?

It was all incredibly confusing – but the further Castiel got from the library, the more the confusion faded away, taking with it the overwhelming sense of dread that had weighed him down. After days of desperately, instinctively clinging to Sam, panicking every time Sam had tried to leave him for even a few minutes – the quiet and solitude were an unexpected balm to Castiel's frayed thoughts and emotions, soothing him and stilling the clamor in his mind. Reassured by the fact that Sam was far out of sight, and he was alone, Castiel allowed the blanket to slip from his wings, clutching it in one hand as he slowed his pace, taking his time and finally venturing into one of the small, dark rooms that lined the hall.

He'd made the excuse that he wanted to go exploring; it couldn't hurt to give himself a little distraction by doing just that.

Most of the side rooms off the hall seemed to be for storage, filled with stacks of boxes and books, shelves lined with various containers that Castiel knew better than to open and investigate. Who knew what might be inside? And the last thing Sam needed right now was another supernatural mess to clean up.

One room, close to the bedrooms, was a little den area, furnished with an over-stuffed sofa covered in worn, soft leather, and a television and DVD player. There were stacks of board games along one wall, many of which Castiel recognized with a fond smile, and a pile of worn throw blankets and pillows in various colors along another. It was a place designed for relaxation, and it warmed Castiel's heart to know that the Winchesters had it – that they had this place at all.

They deserve it. They've earned it.

Both of them.

He swallowed slowly, an aching knot in his throat, his eyes burning, as he knew simply by instinct, by his knowledge of the brothers, that Dean had had the greater part in setting this room up. And in light of all that had happened, that intimate knowledge was a stinging pain in his heart, an ache of loss when he imagined Dean sitting in here watching a movie, laughing at something he found amusing – and realized that even if Dean did get back the laughter and lightness he'd had before this… it wouldn't be something that Castiel would ever be a part of again.

Castiel made himself go on, and after a little while, found himself in a large, industrial kitchen, well-stocked and immaculate. Castiel started to continue down the hall – but then stopped, reconsidering. He thought of Sam, sitting alone in the library, poring over dusty, dry texts with tired eyes, working without complaint to try to make things easier for Castiel, while consumed by worry over his brother's safety. He smiled as he opened the cupboard over the stainless steel coffee maker, and found a box filled with various flavored teas.

Maybe there was something he could do for Sam, after all.

Castiel set his crumpled blanket on the counter and searched the cupboards until he found a large mug, and then filled it with water. It was at that point that he found himself extremely grateful for the printed instructions on the box, as he had no experience whatsoever in the process of making tea. Even with their assistance, it took him a few minutes to get it right. But eventually, one steaming, fragrant mug of hot tea in one hand, and a fistful of sugar packets in the other, Castiel headed back down the hall toward the library.

He found Sam exactly where he'd left him – his head resting on the open book in front of him, arm folded over his head on the table… sound asleep.

Castiel set the steaming mug down, safely out of reach of Sam's long arms, before going to Sam and touching his shoulder. Sam startled awake, blinking up at Castiel in confusion.

"Come," Castiel said softly, tugging at Sam's arm to get him to his feet. "You need to sleep, Sam."

"Was sleeping," Sam muttered, but he allowed Castiel to pull him up, instinctively wrapping an arm around Castiel's shoulders to steady himself, but stumbling a little anyway.

Castiel supported him more easily than he'd expected, feeling stronger than he had in days. "You can't sleep there," he informed Sam matter of factly. "The weight and length of your body are too great to be accommodated by that position. You'd awaken with considerable discomfort in your spinal area."

"Uh-huh," Sam mumbled, clearly not having caught much of what Castiel had said. He woke up a little more as they started walking, Castiel guiding Sam toward his room. "Cas – I need to research…"

"Not right now, you don't," Castiel insisted firmly, leading Sam the rest of the way down the hall and toward his bedroom doorway. "Right now you need to sleep. You can't continue to function properly on as little sleep as you've been getting."

"But… if Dean calls…"

"I'll keep your phone with me," Castiel offered quietly.

Sam looked down at him with a worried frown, eyes sleepy but still concerned as he stood up straight, awake enough to realize how much weight he'd been letting Castiel bear, and removing his arm from Castiel's shoulders. "Cas… if he calls…"

"I can't guarantee I'll answer, no," Castiel admitted as they reached Sam's room and he guided Sam inside with a hand on his back. "But I'll bring your phone immediately to you and tell you…"

He froze just past the door, taking in the sight of Dean's discarded clothes littering the floor, the familiar scent of Dean that permeated the room as much as Sam's did – but he fought through it, pushing it to the back of his mind as he led Sam to the edge of the unmade bed and sat him down on it. Sam blinked sleepily up at him, a lazy smile on his lips, and Castiel realized that it was as relaxed as he'd seen Sam look in quite a while. Sam fumbled in his pocket for a moment before producing his phone and placing it in Castiel's hand.

"Thanks, Cas," Sam said softly. "You don't have to do this."

"I'm not doing anything," Castiel insisted, pushing at Sam's shoulder to get him to lie down. "You're exhausted. Dean isn't even here. You don't need to care for me, because I'm fine. What you need is to rest."

"Okay," Sam agreed, too exhausted to argue, lying down on his side on top of the tangled mess of sheets and coverlet.

Castiel glanced around the room before he noticed a thin quilt hanging over a chair in the corner. He picked it up and spread it out over Sam's body, smoothing it down as Sam had done so many times in the past few days, when covering Castiel's wings. He hesitated a moment, unsure what to do next. He thought about lying down on the bed next to Sam, but knew that if he did so, he risked falling asleep himself – and he couldn't do that, not with Sam trusting him to watch for Dean's call. He thought about taking a seat in the chair across from the bed, but it felt too far away; something in him, some rising part of him that had been growing in strength and intensity these past few days, wanted to be close to Sam – in contact.

Finally, Castiel settled on the floor at the side of Sam's bed, turned to the side so that he could lean against it without crushing his wings. Sam was already sleeping – far more exhausted than he'd realized – and Castiel reached out a cautious, tentative hand, threading his fingers lightly through the fingers of Sam's hand, studying his face closely.

Even as he drifted further into sleep, Sam was restless and anxious, his brow furrowed with worry. Castiel set Sam's phone down on the floor beside him, then closed his eyes, focusing on the faint glow of his grace he could feel building deep down – a flickering spark that he quietly, intently willed to flame. Mentally holding onto that flame, envisioning the power he knew it had once held, Castiel reached out a hand and passed it tenderly across Sam's brow.

Instantly, the tension eased, Sam's face going slack, the creases fading, as he slipped into a deeper sleep than his worries and fears would have allowed. Castiel found himself shaking, his breathing heavy, light-headed – and decided that he didn't need to do that again anytime soon – not before his grace had had a little more time to recover.

Still… he didn't regret it.

After all that Sam had been doing for him, he was finally able to do something for Sam in return, even if it was a very small thing like grant him a few hours' peaceful rest.

"It's okay, Sam," Castiel whispered, his fingers tightening gently around Sam's, as he reached down to take up Sam's phone again and then rested his head against the side of the mattress. "Sleep, now. I'll watch over you."