Over half an hour later, Dean still hadn't stirred. His breathing had finally found a wheezing rhythm that, although it couldn't be called regular, was persistent. His head hung forward, his chin resting on his chest above the amulet. Sweat dripped from his forehead to the cold grey concrete below like an unreliable metronome.

Sam had dragged his chair to the very edge of the Devil's Trap. He would have settled inside it with a hand on his brother, but Cas hadn't allowed it. He still seemed to fear a final surge of power and spite from Dean, and didn't want Sam within reach.

A crushing pain had settled over Sam's chest. It felt almost as if his ribcage was bound again, but this time there was no relief from the weight he knew was caused by his brother's suffering. And from the fact that he was responsible for it.

Being warned that Dean might not survive the cure and ignoring it and trusting in his brother's steadfast strength was entirely different from this side of the cure. Now his mind whirled in painful circles. What if he dies? I won't be able to bring him back, no one will. If the cure itself is this hard on him, how will he survive the aftermath? But I couldn't leave him as a demon and the only other choice was to find a way to kill him ... I'd rather die than kill Dean. I had no choice. But what if he dies?

He had spoken these fears aloud to Cas but the angel could offer no comfort other than the reassurance that this chance, however painful or slim, was preferable to a black-eyed Dean.

Sam wondered if this was how Dean had felt when he had convinced Death to return his soul, regardless of the warnings that Sam couldn't take it. He suspected it was. How had Dean coped with it? This crushing doubt and fear? A final Hail Mary that could end his world or save it? Not for the first time, Sam marveled at his brother's strength and faith in him.

Watching the irregular, slight rise of Dean's chest stirred a memory Sam hadn't thought of in years. He almost chuckled as he remembered it. He cleared his throat. "Hey, Cas?"

"Yeah?" The angel looked about as cheery as Sam felt.

"Did I ever tell you about the time Dean got hurt on a hunt and Dad wasn't around? When we were kids?"

"No?" Cas shifted in his seat, inviting Sam to distract him with the story.

"He was ... fifteen, I think. Maybe sixteen. He and Dad had gone off after a ..." He frowned as he tried to remember. "A ... vengeful spirit, yeah. Anyway, things were going fine – they'd found the bones and torched 'em. But then, BAM!" He clapped his hands together, making Cas jump slightly. "Dean gets thrown right across the room, through the wall and falls half a storey into a lake. In Michigan – in winter. He probably broke through a layer of ice.

"So Dad is totally freaked, he legs it down to the edge of the river, and Dean is somehow still awake, trying to keep his head above the water. He's half made it to the shore, and Dad wades in and drags him out. I was waiting in this crummy little shack we'd holed up in – there were no motels for miles, this place was in the middle of nowhere. So Dad drives Dean home at, like, one-eighty miles an hour, and Dean's shivering and trying to stay awake. Dad calls me and tells me to get a fire going in the old grate, and get all the towels and blankets we had and drag a mattress into the living room – Dean's hurt.

"So I'm already panicking on the other end of the line when he says that, and in my mind Dean's, like, dying of some Tarantino-worthy gory wound. So when Dad arrives and carries in this dripping wet, shivering Dean who's paler than snow, for a second I was relieved. Till I saw Dean's face. He didn't smile at me like he always did when he got back from a hunt hurt. He'd always let me know he was okay, but not this time. His eyes were half open and his breathing was so ragged and shallow, I thought he was gonna die right there in Dad's arms." Sam felt cold himself as he relived the memory.

"What did you do?" Cas's eyes were wide, drinking in the story.

"Froze. But Dad snaps me out of it, makes me help get Dean's clothes off so he's just in his boxers and we wrap him up in, like, six towels and blankets so he could barely move. Dad laid him down beside the fire and told him he was gonna be fine now, that he just had to stay still and get warm. He told me to heat up some soup from a tin for him.

"Anyway, once we'd convinced Dean to eat a few mouthfuls of Spicy Chicken and Noodle, he passed out. Then Dad stands up and says he's gotta go finish the hunt, figure out what he missed. At which point," Sam added, raising his eyebrows at Cas, "I basically explode. 'How can you leave Dean like this?', 'what if he doesn't wake up', yelling at the guy for, like, a minute.

"But then Dad goes –" Sam shifted his weight and imitated his father's deep, commanding voice. "'You listen here, Sammy. I gotta go clean up my mess. There's nothing I can do for Dean now, he's out of danger, he'll be fine by tomorrow, but right now I gotta go. I'm leaving you in charge of your brother. Take care of him,' he says. And Dad's never said that to me in my life – it was always Dean who had to take care of me." Sam smiled sadly.

The corner of Castiel's mouth curved in a small smile, brightening his serious expression for a moment. Sam's widened at the sight, glad to be succeeding in distracting them both from the softly groaning Dean.

"So Dad leaves without another word, grabbing an extra shotgun on his way. And I look over to Dean," he continued, his head turning towards his unconscious brother. "And I'm terrified. I have no idea how to help him, and he looked so ... I dunno, young, maybe. But he was sleeping, and I just sat beside him and stared at him for like an hour.

"When Dean does wake up, he's coughing and groaning and somehow looks even paler. He asks where Dad is and I say he's gone off to kill the ghost, and Dean just stares at me. 'You let him go alone? Help me up, Sammy, I gotta go help him'. But when he tries to sit up he cries out, and I start flapping around him, not knowing what to do. It turned out his shoulder was dislocated from going through the wall. Dad kept the painkillers in the Impala, so there was nothing I could do till he got back."

Sam gulped, his stomach twisting with the remembered fear.

"So then Dean goes, 'You'll have to do it, Sammy. You're gonna have to pop in back in.' And I've never done anything like that and I was so scared I was shaking almost as bad as Dean had been. But then Dean puts his good hand on my shoulder and he says, "'Sammy, look at me. I know you can do this. I got no doubt. Just do as I tell you, okay?'"

Cas nodded, smiling fully know at the thought of such an inexperienced and flummoxed Sam Winchester.

"So I nod and he tells me to put one hand here and the other there on his shoulder," he said, mimicking the old instructions, placing his hands around an imaginary brother. "And then he says, 'When I count to three, you gotta push it back in, as fast as you can'. He could feel my hands shaking on him, but he just turns to look at me and he, he gives me this smile." Sam looked back to his brother, his eyes full of admiration. "This smile that says, I know you can do this, Sammy, and it's okay. It's gonna hurt, but it's okay, you can do it.

"So he counts to three and I shut my eyes and yank his arm and it pops back into place with a crack and Dean yells in pain and I jump back, sure I've just broken something.

"But then he flexes his arm, showing me how his fingers all move perfectly and his shoulder rotates just fine, smiling the whole time, even though I could see the pain in his eyes. I was still shaking so he gives me the biggest hug and says 'Thank you, Sammy. You're the best.'

"I'd never felt so grown up.

"After that, Dean fell asleep, wrapped in all the blankets but one – he insisted I wrap myself up too 'cause it was so cold. Of course, it was roasting in there, he just couldn't feel it.

"I don't know how long it took Dad to come back, but I just remember sitting there for ages, just watching Dean sleep. I kept thinking how easily he could've died that night. If Dad hadn't gotten to him in the lake fast enough, if he'd hit his head on the wall on the way down. If the heat in the Impala had been out, he could've died of the cold."

Cas remained silent, allowing Sam to tell the story at his own pace. The young Winchester's eyes were unfocused, staring into memory.

"But he didn't. And I remember thinking, 'Wow. Dean must be as strong as Dad. I bet he wasn't even scared.'" Sam chuckled. "Looking back on it now, he sure as hell was. But not for himself: for Dad. Whenever Dad went off on a hunt alone, Dean would hold his breath till he came home safe. Or, came home, at least.

"When Dad finally did get home, it was hours after my bedtime and I was barely keeping my eyes open. Dad's nose was bleeding and he was limping a little, but he went straight over to Dean and checked on him, taking his temp and tucking the blankets in around him. Then he gives me the biggest hug and says, 'Thanks for taking care of him, Sammy. You did good.'"

Sam swallowed past the lump in his throat.

"After that, Dean started teaching me more first aid. How to bandage up a bad cut, how to check for concussions, when to know to call for help, how to stitch up a wound ... By the time Dad started teaching me triage, I already knew it all. Dean'd already taught me."

Sam looked up at Cas. "He didn't teach me what to do now."

Cas tilted his head, his eyes filled with compassion. After a moment's hesitation, he got up and curled his arms gently around Sam's shoulders, hugging him tightly. Sam grabbed on to Cas's arm as if his life depended on it, trying to breathe normally.

They remained holding onto each other for a long time, neither wanting to break the embrace, both needing the comfort of a friend's arms helping hold themselves together.

Too soon, too loudly, Sam's watch beeped shrilly. For the last time.

Breaking apart, both angel and hunter reached for a syringe. Cas went first, forcing his Grace into Dean's blood to burn away what remained of the demon taint. Dean stirred, frowning slightly and moving his head away from the angel. When Sam pushed the plunger home for the last time, Dean jerked as though yanked by invisible ropes.

Feeling an odd calm pass over him, Sam unsheathed Ruby's knife from his belt and passed it over his left palm, leaving a line of thick, bright red. Gently pulling Dean's head back, Sam began the spell that would either save his brother or kill him.

Dean's breathing quickened and his eyebrows twitched as the word-borne magic took effect. Sam felt excitement and fear rise in his chest, shattering the calm.

"Hanc animam redintegra – lustra! Lustra!"

Sam slapped his hand across Dean's open mouth, and at the same time Dean's black eyes opened, the world exploded.

Sam was thrown backward as a great shockwave erupted from Dean, punching through the air like silent thunder. He hit the wall hard and crumpled to the floor, struggling to his feet immediately. Apart from a throbbing elbow, he wasn't hurt. Cas had been thrown back almost to the door, but he too was getting to his feet, staring at the Devil's Trap.

The chair Dean had been tied to had shattered. Dean lay over the wreckage, convulsing violently, his black eyes staring up at the ceiling, foamy blood pouring from his mouth, making him gag and choke.

Sam ran forward, snaking his arm behind Dean's shoulders and scooping him up into his arms. He braced Dean against his chest, trying to support him through the vicious tremors. Dean's breath was a ragged gurgle, and he seemed completely unaware of Sam's arms wrapped tightly around him.

Another, weaker concussion rippled out from Dean, ruffling Sam's hair and thudding into his chest.

"Dean?" he whispered, giving his brother a little shake.

The black eyes didn't move from the ceiling. They stared unblinkingly as Dean lay in Sam's arms, unmoving save for his uncontrollable shudders.

Sam looked frantically around at Cas. "What's happening!"

"Look!" Cas gasped, pointing to Dean.

Sam whipped his head around and his eyes widened in amazement.

The deep blackness that consumed Dean's eyes was breaking up at the corners like melting ice. Smokey tendrils withered and shriveled away, slowly receding until the familiar, bright green eyes stared up at the ceiling.

"Dean?"

Dean blinked, looking confused and lost. His hazy eyes searched until they found Sam's. A tiny, relieved smile curved Dean's lips as he drank in the sight of his brother.

"S-Sammy?" His breath hitched and the single word seemed to drain what little strength he had, but Sam beamed down at him, feeling a tear tickle his nose as it fell.

"Hey, Dean," he half-whispered, half-sobbed, feeling the first sincere smile in a year stretch across his lips.

Dean's smile widened slightly. But then his eyelids drooped, his eyes rolled back, and he went completely limp in Sam's arms.