"Welcome back, Dean."

Dean blinked blearily, the world a dark, hazy blur. His brain droned like a hive of wasps had taken nest behind his eyes. He wrung his head in an attempt to clear it, his hair scattering holy water across the room. Finally, his gaze began to focus, the colors coalescing into two familiar figures before him. Relief watered his eyes, and he smiled weakly at the sight of his little brother, "Sammy."

Then, like the bursting of a dam, came a crushing flood of memory and lingering rotten emotions, springing a new set of roiling shame, regret, disgust, and overwhelming guilt. It choked him, dislodged the tears from their ducts, made him want to tear from his body whatever organ housed this awful feeling and chuck it deep into the ocean.

"Sam," his voice cracked on the name, staring at the swimming blur of his brother. "Sammy, I'm sorry." His words felt so feeble, so weak, so horribly insufficient to convey his remorse.

Sam nodded, his own eyes wet, a tight, forced smile on his face, "It's okay, Dean. I, uh… it's just… good to have you back."

It wasn't okay—it was anything but okay. But he couldn't form words, not reliably, and all that came out was a thin echo, "Sam…"

Sam shook his head, his voice low, "It's not your fault." But it was—he wished he could believe Sam, but it was. Sam angled his head and tried to lighten his tone a degree, tried to shift the conversation, "How are you feeling?"

Like he'd been boiled alive. "Better, uh… human." He offered another weak smile.

"Good. Good." Sam bobbed his head faintly a couple times, working his palms uneasily. Splotches of blood still marred his face. Given the smear and inflamed skin, he'd apparently tried to scrub it off, but he clearly hadn't seen a mirror since… since. Maybe he noticed Dean's gaze, because his eyes dropped, and he retreated a step, "I'm, um… I'm gonna go get cleaned up, okay?"

Dean nodded, though it wasn't really a question. Sam barely glanced back as he exited the room, his shoulders hunched and head low. The minute he was out of sight, Dean released a heavy exhale, tears still mocking him. Guilt condemned his stare for making Sam so anxious, for driving him away. It condemned him for putting Sam in this position. It condemned him for doing this wretched thing to his little brother instead of protecting him like he was supposed to.

"Are you okay?" Castiel asked quietly, evidently skeptical of Dean's prior answer.

Dean chuckled self-deprecatingly, "I've been better." He rubbed a hand over the back of his neck, then raised his gaze to glance over the angel, "What about you? Are you… back?" Last he'd heard, Castiel's borrowed grace was failing. But now, he seemed as strong as ever.

"For now." At Dean's frown, Castiel supplemented, "I… received the grace of another angel. Much like the last… its effects will be temporary."

Dean caught the careful wording and the tension underlying it, but his questions could wait. "Well… I'm glad you're back, Cas."

The angel acknowledged the sentiment with a nod, before he took a slow step closer, broaching guardedly, "Dean… how much do you remember?"

"Of… being a demon?" Dean swallowed, unable to conjure a snarky reply. His voice was hoarse, "Most of it. Maybe all of it."

"I'm sorry."

Dean shook his head. He wasn't a victim here—he didn't deserve apologies or pity.

"Cas, the things I did…" Bile flooded his throat at the memory. "What I did to Sam…"

"Sam's right—that wasn't your fault."

"How can you say that?" Dean stared at Castiel incredulously. "I force fed him demon blood."

Castiel's expression was solemn in pity, "It wasn't you."

"It sure felt like me."

"It wasn't you," Castiel repeated, "You would never do something like that to Sam. He knows that."

"I wasn't possessed." Demon or not, it was still him. "I still remembered everything, I knew he was my little brother, and I knew exactly what I was doing. I just… I didn't care." He searched Castiel's face, "I enjoyed it, Cas."

The angel breathed a slow exhale, taking a moment to consider his reply, before he tilted his head with a sudden resolve, "And what about now?"

Dean frowned, "What are you talking about?"

"Do you find joy in those memories? Do you still want to hurt your brother?"

"Cas," Dean flinched back, the very thought abhorrent, "Gosh—no."

Castiel slid a hand through the air to signal Dean had incidentally conceded.

Dean merely shook his head again, leaning against the chair with his head hung, "That doesn't change what I did."

"I know. But it wasn't you. And we'll deal with it." He glanced over his friend and the despondent slump of his shoulders and cast of his head. "Perhaps you were still in there, fighting back, even when you were a demon." Castiel noted, catching Dean's wary gaze. "You could've killed Sam, I assume, if you got close enough to…" he trailed off, leaving the sentence unfinished, the crime unspoken. "But you didn't." He paused, raising his shoulders slightly, "Maybe some parts of a person are so integral they can't be taken away."

Dean's eyes sank back to the floor. Several more tears launched their escape from his eyes, "I tried to kill him, Cas. And I would've—he barely… but when he had the chance to kill me… he couldn't." Dean stared at Castiel as though he might have the explanation why. "And it made me furious. That he was playing the bigger man, pretending to be something better than I was. I knew the things he had done, and I wanted to show him he was just as much of a monster as I was." Dean's voice trembled. He wasn't sure what drove his confession—he wasn't even sure what he wanted to hear in response. A condemnation, disgust, anger? Compassion, assurance, acceptance? His breath was thin as he tried to recompose, to reach a conclusion. "Sam would've rather died than drink demon blood again. And I knew that, Cas. I wanted to hurt him. I wanted to make him suffer. Or maybe… maybe I just wanted to see what would happen."

He closed his eyes, waiting for his penance or absolution, but it didn't stem the tears racing down his cheeks. He gripped his head, curling over himself. He could still remember the thrill of his vivid delight at the panic in Sam's eyes. He thought he might be sick.

"Dean." He felt a hand on his shoulder, "You weren't in control. Sam knows that."

Dean finally mustered the will to glance back at Castiel, searching his face. How could he just dismiss what Dean had done so easily? How could Sam? Were the situation reversed, Dean would be furious with either one of them. Couldn't they see he deserved it? Maybe they just didn't know the extent of it. Maybe they just didn't understand.

Still… even if they should be shouting or cursing or cutting ties… he couldn't deny, he was glad they weren't. "Cas… thanks."

The angel inclined his head, smiling softly as he echoed Sam's earlier statement quietly. "I'm glad you're back, Dean."

At Dean's faint nod of acknowledgement, Castiel took the signal to remove his hand and step back, granting the Winchester space to recompose. Dean cleared his throat, straightening as he wiped his face with his shirtsleeve. When he spoke again, his voice was stronger, level, almost normal. "Problem is…" Dean rolled up his right sleeve to reveal the swollen brand, "The cure didn't fix this."

Castiel's expression turned solemn as he gazed at the Mark, then at Dean's face, "I know."

"That means this could happen again. And Cas… I can't do this again." Not that the Mark would give him much choice. He needed it gone. He wished desperately that he'd never accepted the accursed thing.

"I understand." The angel's eyes flicked back toward the doorway, "Sam has been scouring for a cure while looking for you. Now that you're back, and the Mark is here… maybe he'll find something."

Dean breathed a slow exhale, trying not to immediately discount Castiel's assurance. Maybe Sam would figure it out. Surely someone had to have written something helpful about an age-old curse. And if they had, his little brother would find it.

Except, of course… Sam had other things to worry about, now, thanks to what Dean had done. He clenched his jaw, biting back the torrent of guilt. "Cas… what are we gonna do with Sam?"

Castiel shifted, head dropping for a moment as he considered. "Sam has gotten through this before. We'll help him through it again."

"But how?" Dean pressed, "What, are we supposed to lock him up in here for a few days? Chain him up like he's no better than I was?" Dean shook his head, gut constricting at the thought. "He didn't ask for this. He doesn't deserve this." After all the hell Dean had just put him through, the kid deserved ice cream for breakfast for the rest of his life. Not to be treated like the very monster he had given almost everything trying to save.

Before Castiel could proffer a response, Dean again shook his head, raking a hand through his hair, "But we've gotta get him clean. We can't go down that road again." How quickly would his addiction sweep in? Would one relapse be enough? It felt like too much to hope that Sam could just lay low for a few days as it cleared his system—that then, he'd be right as rain, sober as ever.

"Perhaps we should consult Sam." Castiel began tentatively, monitoring Dean's reaction as though to gauge the rationality of the suggestion.

Dean swallowed the scorning chuckle before it departed his throat. Sam was an addict—how could they trust his judgment when the craving could cloud his head? And it wasn't like they were going to give Sam a meaningful choice—not really. He was getting clean, no matter what.

"Last time, he walked into the panic room voluntarily." Castiel remarked, "It might be best if we allowed him to choose this willingly too."

Dean exhaled through his teeth. Castiel was right—it'd be better than Dean or Cas restraining Sam, dragging him into a dungeon and chaining him up like a beast. No… Dean didn't want it to come to that. Not when this was all Dean's fault.

"Alright," he acquiesced, "We'll talk with Sam about it." He didn't bother adding the obvious—that if Sam resisted a detox, they'd have to revert to a more forceful plan B. It wasn't that Dean expected Sam to so quickly cling to the blood—after all, Dean was the one who had blocked Sam's airways to force it down his throat over Sam's struggling attempts to resist. He knew Sam hadn't wanted the blood. Even now, he believed Sam wished to heaven it wasn't inside him. Dean just didn't trust that poison worth a dime. He knew how it could twist and torment his brother, he knew that it could screw with his mind—he knew there was a reason it scared Sam so badly, even if Dean wasn't entirely certain what that was.

Castiel nodded his assent, and Dean glanced toward the doorway, realizing, "…we should probably check on him."

The angel looked back toward Dean, his face uneasy with the distrust implicit in the statement. But even without the demon blood, Sam had endured enough today to probably merit a check-in. He'd assuredly burned himself out in trying to save Dean. Dean's gut twisted. Without anyone around to support him, Sam had probably barely eaten anything, barely slept outside of passing out at his laptop or over a dusty tome. Guilt gnawed at his heart. It couldn't be a great foundation for an already wretched and brutal detox.

Dean started for the door, trying to ignore the exhausted ache of his legs, of his body that threatened to collapse at any step. He supposed he hadn't slept either—for months. And he wasn't a demon anymore. Now, he felt like he could sleep for a week—if he wasn't scared of what he might see when he closed his eyes.

Castiel's eyes raked over Dean, clearly noticing the stumble. "Are you alright?"

"Fine—just a little tired."

Castiel cast another scan, "Perhaps you should consider taking it easy for the next several days. The ritual of purified blood likely took a substantial toll on your body." Before Dean could object to the notion, Castiel added, "Once Sam is recovered, you both should take some time. You've earned it. Besides, the world seems relatively stable right now. You'd probably be doing it a favor by taking the time to get back on your feet."

"Don't jinx it, Cas," Dean muttered, but maybe it was true. It had felt like one apocalypse after the other, but now, heaven and hell seemed quiet. Aside from the Mark, once they resolved Sam's addiction, things might actually qualify as calm for the first time in what felt like a decade. Maybe they did deserve a break… he'd like that.

He rested a guiding hand on the wall as he urged his weary legs onward, his gaze sliding over the halls he hadn't seen in weeks. He'd missed this. Home. When they entered the library, Dean frowned in surprise at the mess. Empty bottles of booze littered almost every surface with careless abandon; dark shards of glass encircled a wall, nudged loosely out of the way. Stacks of books lingered precariously near the edges of the tables; several heavy hardcovers hung open, a few pages of scrawled writing scattered seemingly randomly about. The disorder itself didn't bother Dean, but… Sam had been the only one living here for the past couple months. This… tornado's aftermath surely would've driven him mad.

Dean cursed beneath his breath, hating himself for how much he'd put his brother through.

He paused before he entered the hallway that would lead to their bedrooms. Castiel halted beside him, his face a frown of confusion.

"What is it?"

"Maybe you should be the one to check on him." Dean glanced down the hall, his voice quiet.

Castiel looked ready to protest—Dean could practically hear him grumble "You humans make everything so complicated" in his expression alone—but he evidently changed his mind as he disappeared down the hall.

Dean leaned against the cold wall. Sam… probably didn't want to see Dean right now. And Dean wasn't exactly sure how to face his little brother. "I'm sorry" felt like a bandaid on a bullet wound. But what else could he say? How could they just move on?

They'd get through this, Dean knew, despite his tension. But it might take time. Just as long as he knew his little brother was safe, he was willing to give it.

"Dean!"

In an instant, Dean's stomach plummeted, dread chilling his veins. His wobbly legs pumped with a jolt of adrenaline, his vision narrowing, his mind screaming with macabre images.

Did Sam…?

No. No, Sam had to be fine. He was fine, he was fine, he was fine.

He cursed himself for letting Sam be alone after everything. What was he thinking?

To think that he was the reason almost made him collapse right there.

But his legs carried him onward, and in a few seconds that felt like eons, he swung into the open doorway.

It was empty—Castiel was alone.

He clasped a hand over his mouth, unable to deny the spring of relief in his chest. Then, concern and apprehension immediately resurfaced.

Luckily, Castiel hadn't seemed to notice the conflagration of emotion behind him, the angel's gaze skirting over Sam's desk.

Dean glanced over the space again, but when Sam didn't magically appear, he leaned out the doorway and shouted, "Sam?"

The silence was suffocating.

"Dean," Castiel repeated, garnering the Winchester's attention as the angel proffered a torn scrap of paper.

Dean's hand grasped it, almost crumpling the page with the nervous force of his grip, his eyes skating across the scrawled words.

Needed some air. Back in a few. Don't worry – I'm fine.

It was Sam's scratchy, half-cursive scrawl. Dean balled the note in his fist, shoving it into his pocket as he started immediately back for the hall.

"Maybe we should wait for him to return?" Castiel suggested as he jogged to catch up to Dean's brisk pace.

Dean scoffed, not dignifying the proposition with a reply. Sam could be chasing another hit as they spoke. Who knew how quickly and severely addiction could reignite? What were they thinking leaving Sam alone?

"Did he take a car?" Dean demanded, snatching the Impala's keys from the war room table. He bounded up the stairs two at a time before yanking the heavy door open.

"He's only been gone a few minutes," Castiel reminded, his attention seemingly almost entirely fixed on Dean instead of their missing blood junkie.

If Dean heard, he gave no indication, breaking into daylight that was greyed with a heavy blanket of clouds.

The Impala waited faithfully along the edge of the narrow road, with Castiel's Lincoln parked a few feet behind. Dean didn't hesitate, pointing down the road before he slid into Baby's driver's seat, "You head that way. You got your phone?" At Castiel's nod, he continued, "Good. Call me if you spot him."

He didn't wait for Castiel's reply, keying the engine—the familiar hum offering a cold comfort—and roaring down the road. The car's growl muffled Dean's cursing, his anger mostly directed internally. He couldn't even apologize to Baby for his lapse in affection, couldn't treat her with the care she deserved. Dean gripped the wheel tight, his gaze scanning the area in hasty glances. His fingers rapped against the steering wheel in impatience, his mind abuzz with horrible images—about where he might find Sam… about what state he might find him in. The thought made him grit his teeth and lean into the pedal.

He'd find Sam. He just hoped it wasn't too late.