A/N: This was written for the spn_gen_bigbang over on LJ. For more details and the awesome art by apieceofcake, do have a look here: emmram (dot) livejournal (dot) com (slash) 37261 (dot) html.

Warnings: SPOILERS for all of s4 and s5, blood, gore, violence, some foul language, character death, heavy-duty angst, weirdness, metaphor-abuse.

Disclaimer: I don't own Supernatural or any of its characters.

Built To Fall

"I hope you're ready."

Yeah, sure.

"I mean, this isn't some place you can just jump back from when someone wants you to. This is it."

I know that, already—just get on with it.

"No reconsidering?"

For god's sake—

"This is important."

I have to do this. It's never been more vital, and might never be again.

"Good luck, then."

Dean Winchester woke up to a bright blue sky and the sound of birds.

It was cold and damp, and there was a nagging thought pulling at the corners of his mind that there was some place that he ought to be, something else that he ought to be doing, but Dean let himself drift, watching the clouds. There was one cloud that had a rather pleasing resemblance to a pair of well-endowed breasts stuffed into a white camisole—Lindsey Turner, maybe? No, definitely Megan Stockton from that time in Oklahoma when he and Sam—

Sam.

Dean sat up quickly, coughing as he sucked in cold air. He realised he was on a bench in the middle of a park, getting suspicious glares from early-morning joggers and the occasional critter as they went by. He wasn't sure what kind of drinking binge could've gotten him here: he felt okay, if a little light-headed, but he couldn't for the life of him remember the last thing he'd been doing. It wasn't a hangover, and it wasn't the aftermath of a particularly nasty hunt; and if Sam had just left him out here in the name of some stupid prank, he was going to—

There was a sudden stab of white-hot pain in his abdomen and he curled forward, hissing. It intensified until his fingers were scrabbling at the bench, nails scratching fruitlessly against the wood. It faded slowly, leaving him sweating and panting.

(remember what i taught you)

He lifted his shirt to see what had felt like a great big, guts-gaping-out kind of wound right across his—

(NO! Please, no, no—stop it!)

There was nothing there. He looked perfectly okay—too okay, really: even that winding, knotted scar from when he was nearly eviscerated by a werewolf at the ripe old age of seventeen was gone. Dean couldn't help but feel that there was something he was missing here, something important...

(you're going to hell. and this? is what you're going to become!)

Dean nearly fell off the bench as he remembered.

He sprang to his feet and grabbed the nearest newspaper he could find. It was the Pontiac Daily Leader, and it was dated the fifteenth of May, 2009.

A year. He'd been gone (dead) a whole year.

It was when he began digging in his pockets for clues that he realised he was even wearing the same clothes that he'd worn that night, except they weren't hanging off him in great bloody strips: no, perfectly okay, just like the rest of him, and what the hell was he even doing—

Right. Okay. He was panicking, and clearly, that wasn't getting him anywhere. He needed to—he needed to find Sam (i swear to god sammy if you've done something monumentally stupid), get in touch with Bobby, try to figure out just how he managed to get topside when by all rights he should be languishing in Hell right now, and why the hell he couldn't remember any of it.

(Not that that was a bad thing, he reflected a moment later. Y'know, hell and pain and torture—nobody really wanted the details.)

He had nothing on him except his boot knife, but that didn't really matter, well-versed as he was in the Many Arts of Bull-Shitting Your Way To What You Want (copyright, Winchester, Winchester and Winchester), and so half-an-hour later, he found himself hotwiring a shiny new Honda and driving down Route 116, on the way to Sioux Falls, South Dakota. He stopped on the way for food and beer when the road began to dip and sway and sort of plunge into the surroundings in a nauseatingly disconcerting way, but didn't stop or slow down otherwise until he was pulling into Bobby's salvage yard.

It hadn't changed much over the last year—hadn't changed much at all, really, since the first time he'd been here, seven years old and scared out of his wits. The half-rusted remnants of engines and machinery and the hulking, bent-out-of-shape chassis from when they used to think bigger was better had seemed like monsters then. Now, they were just dead and broken pieces of metal. Dean wasn't sure which of the two he preferred.

He'd already walked up to the front door when he realised that showing up on Bobby's doorstep after being dead for a year without so much as a phone-call was probably not a great idea; there was no telling how Bobby would react (with shotguns and holy water and silver knives, how the else did he expect him to react), if he even knew where Sam was, if he was even alive—

The door opened. "You're going to be standing out there all day, boy, or are you going to come in?"

Dean blinked. "Bobby?"

Bobby smiled. He didn't look much different, either: his face was more lined, tired-looking, Dean imagined, but he wasn't sure what the hell that even meant. People got old. Even Bobby, even if it was hard to believe sometimes.

"It's good to see you, Dean," he said, spreading his arms. Dean hugged him a little tentatively, wondering if it was his turn to be breaking out the salt and holy water. "Christo," he said, and Bobby only chuckled. "He did say you were coming back," Bobby said, pulling back, "and he might be a self-righteous stick-in-the-mud, but he's never been wrong before."

Dean looked over his shoulder, frowning. "Who did? Sam—where the hell is Sam?" He pushed past Bobby in his haste to get inside and find his brother. "Did you and Sam do this, huh? Did you just think that, hey, it would be great idea to start bartering souls again? Sam!" There was no answer, and Dean rounded on Bobby, furious. "I thought you'd know better, Bobby, than to have him start repeating—"

"You'd better be thankful that I'm not just throwing you out on your ass for bargin' in here and throwing around accusations like you know everything," Bobby said, raising an eyebrow. "It wasn't your brother who popped you outta hell, though god knows he tried."

"Then who did, huh?" Dean ran a hand through his hair, tried to slow his breathing. "I'm sorry, Bobby. It's just—friggin' waking up on a park bench after the last thing you remember is being torn apart by hell-hounds—"

"I'd hoped it would be more convenient than a closed grave," came a quiet, gruff voice from behind his shoulder, and Dean swivelled to find himself face-to-face with a thin, stubbled countenance about three inches too far into his personal space. He stepped back, blinking. "What the—"

"That's Castiel," Bobby said, and Dean could swear that he heard a grin in his voice. "He's the one who pulled you out."

"What is that supposed to mean?"

Castiel said nothing. His eyes flicked minutely to Dean's shoulder, and Dean felt a sudden, sharp pain in his right upper arm. He rolled up his sleeve to see a burn mark against the skin, perfectly shaped like a human hand. Dean wasn't completely sure how he hadn't noticed a giant red handprint on his arm until then, or what kind of mojo this skinny little guy in the trenchcoat had that had him freakin burn people without them noticing.

"It means," Castiel said, "I gripped you tight and raised you from Perdition."

Dean had barely opened his mouth (yeah, sure, that makes a lot more sense, thanks) when a muffled scream echoed through the house. "Dean," it said, twisted with pain and fear and a kind of hysteria that made Dean's blood run cold. "Dean!"

Bobby flinched. "Basement," was all he said.

Dean barrelled past him. "Sam!"

Dean could hear the screams clearly, now, and wondered how he'd ever missed it. He was in front of what appeared to be a huge iron door in Bobby's basement that he was pretty sure hadn't been there a year ago. Reinforced salted iron, Bobby'd said. Protection against every known evil fugly out there.

It was a supernatural Panic Room, probably one of the safest places in the world to keep evil out (and in)—and right now Sammy was locked up and screaming right inside it.

Dean wasn't sure he wanted to know the whys or hows of the situation just then; all he could feel was a bubbling horror at what shit could've possibly gone down while he was stuck Down Under, and how deep his brother could be mired in it.

He watched as Bobby opened the door, the mechanism creaking ominously as he turned it. "You've got to remember, Dean," he said, "Sam's... not himself, right now. You have to understand—"

"If you're trying to not freak me out, I gotta say, you're not exactly doing a bang-up job of it."

Bobby rolled his eyes and pushed open the door. The screams stopped as he did so, and Dean felt a small rush of air next to him; he turned to see Castiel by his side. "Do not be fooled by what you see, Dean," he said, narrowing his eyes at the open door. "An abomination can come in many guises."

"If you can all shut up," Dean growled, "I'll actually go see what's wrong with my brother." He stalked into the room—it was tall and dank, made entirely of iron, with the sole source of light coming from a slow-whirring fan set high on one wall. The ceiling and floors were adorned with devil's traps and various other protective sigils, half of which Dean was sure he wouldn't even recognise. The only furniture in the room was a cot in the centre—its railings trailing iron manacles—and a table with a mirror.

Sam sat hunched on the floor, leaning against the bed, knees drawn up to his chest.

"Sam." Dean stepped toward him, registering for the first time how the room smelled—of salt and sweat and blood and vomit and citrusy floor cleaner. Sam's clothes were filthy, stuck to his skin with sweat, and his bangs, greasy and overgrown, hung over his face as he stared at the floor between his legs. Dean began to wonder just how long Sam'd been cooped up here, and the presence of the manacles wasn't exactly helping to ease Dean's rising misgivings. "Sam," he said again, crouching in front of his brother, placing a tentative hand on his knee. "Sammy, hey."

Sam was shaking under his touch, minute tremors running through his body like he was cold but too tired to do anything about it. He lifted his head slowly, stared at Dean with a weary, but focussed, gaze. "Hey," he said quietly.

Dean snorted. "Here I am, back from the dead, and nobody even has the decency to look surprised." He lifted his hand to push Sam's hair out of his eyes, and nearly pulled it back with a hiss as he felt how hot Sam's skin was. "Shit, man, you're burning."

"No, I'm not," Sam said, his voice so hoarse and dry that just listening to it made Dean's throat hurt. "You are. Always." He looked a little beyond Dean's shoulder and smiled, although it was a horrible smile, jagged and bitter and about as completely devoid of humour as it could get. "Been watching you for a while. He's very proud, you know."

Dean felt a sudden fear clutch at his throat with icy fingers. "What're you talking about?"

Just as suddenly, Sam's hands shot out, clutching at the lapels of Dean's jacket and pulling him in with astonishing strength. Although Sam was ill and pale, skin stretched tight over bone, Dean couldn't help but notice how much bigger he'd gotten, how much more muscle bunched over his shoulders. "Please," Sam said, and to Dean's shock, he was actually crying, "please, I'm so sorry, please let me go there now, please—I can't, not here—"

Then his whole body went rigid, his eyes rolled back, and he started jerking in uncontrolled spasms.

"Bobby!" Dean caught Sam's hands in one of his own, slid another behind his head so that he didn't crack his skull open on the bed railings, all coherent thought out of his head other than Sam's having a seizure and this is the weirdest fucking day I've ever had, and that's saying a lot. Bobby ran in and got painfully to his knees next to Dean, but Sam had already stopped shaking, lying limp and so still that Dean splayed his hand over Sam's chest just to make sure he was breathing.

And so, yes, Sam did have a flair for melodrama, but this was really fucking too much (and really fucking terrifying). "The hell, Bobby?"

Bobby's mouth twisted in a sort of helpless desperation, and he scratched the back of his neck. "It's... a long story, Dean, and it ain't a happy one."

"Ya think?" Dean retorted, unable to help himself. He looked down at Sam, sighed. "Let's just—let's just get him on the bed, first." He and Bobby got Sam's gigantic form onto the bed between them, and despite Dean's protests, Bobby secured the manacles around Sam's wrists and ankles. "He's going to need 'em," was all he'd say by way of explanation.

"Continuing in this fashion," said Castiel from where he was standing just outside the door of the Panic Room, "is not beneficial to anybody—least of all to Sam, or dealing with what's inside of him."

"Only the ten thousandth time he's said that," Bobby muttered to Dean, rolling his eyes. "The only wonder is that he hasn't tried to kill Sam himself, yet."

And just like that, Dean had had enough. "We could stop dancing around the elephant in the room," Dean said, raising his eyebrows, "and give the resurrected guy here some answers, because, otherwise? I will freak out, and it will not be pretty."

Bobby looked from him to Castiel and back again, and sighed. "How much do you know about the Apocalypse?"

"Dean's back," (he) says, his face twisted into that awful facsimile of sympathy—head tilted, smiling, eyes glittering with black mockery. "Imagine that. Imagine waking up a year after you were killed; imagine waking up and coming back to the brother you went to Hell for; imagine him doing things from your worst nightmares." (He) settles down on the floor, cross-legged, and rests (his) chin in (his) hand. "Imagine coming back to realise that you'd died for a monster."

"No," Sam says, shaking his head, although that makes the world swirl and shift nauseatingly, "It's not him, it's—he can't be." He swallows convulsively. "I failed. He can't. He won't know."

(He) shakes (his) long hair out of (his) eyes. "Oh, Sam. I know how crushing it must be—to know that you did what you thought was right, and to have your family hate you for it, throw you into a prison to die and rot for eternity." (He) smiles again. "You know that was your brother. Deny it all you want, but deep down... you know."

"Please." Sam tries to curl into himself, finds that he can't, feels ice-cold restraints coiled around his arms and legs. He's burning, oh god he's burning, and maybe when every single thing inside him boils over, he'd rise out of the restraints. Maybe he'd become demonic smoke, maybe he'd actually die (oh god he wishes he dies)— "Please get out."

"I would," (he) says, "if I could. But when I am you, Sam, there's only one way I'm getting out of your head."

An inexplicable anger fills Sam's limbs, ignites his nerves like fire, heady like demon-blood. "I'm never saying yes!" He jerks against the manacles, feels like he's about to burst. "You did this to me!" he screams.

(He) shrugs. "I did this to you, you did this to you... what's the difference?"

Sam screams incoherently, feeling the burn concentrate in his lungs and bubble up his throat. He turns and spits, and sees his anger drip red and black and viscous onto the floor. "No," he says. "I will kill you—kill—" He chokes again.

(He) laughs. "Please do try—your anger is delicious."

The fire builds inside of him, feeding itself like a nuclear breeder reactor, until he can't make a difference between pain and power and it's the closest he's ever gotten to having demon-blood again. He pulls in his left hand viciously, feels something break, and then his hand is free. He ignores the pain sparking down the length of his arm, sharp and white-hot, and twists to fumble awkwardly at the manacle around his right wrist. He can feel (him) hovering nearby, can feel (his) hot breath, the—

"Let me help you, Sam," (he) says, and gently strokes the manacle. It snaps open, even as blood bubbles like lava over Sam's lips. (He) repeats the process with the restraints around his ankles, and Sam rolls off the cot onto the floor and rests there for some time, cheek against cold concrete, taking in short, wet breaths.

For a moment, the fire recedes, and Sam thinks: Dean. Oh god, Dean—

Then (he)'s got (his) hands under Sam's shoulders, pulling until (he)'s hoisted Sam to his feet. "I gotcha," (he) says, and something inside Sam aches with familiarity and loss—so much loss—but everything's washed away by anger (like always), pure and clean, and he hates that (he) even dare imitate his brother; hates himself that he lies here, tainted and evil, unable to do anything to deal with the mess that he unleashed on the world; unable to justify any of the love or faith that Dean placed in him.

He surges to his feet, spitting the blood pooling in his mouth, dripping down the back of his throat. (He) smiles—proud, Sam thinks, and his hate only increases—and gestures toward the door. The cast-iron door opens almost without a sound, and Sam staggers out. The burning in his chest is excruciating now, but he keeps moving, one arm wrapped loosely around his chest, the other blindly groping for handholds.

Jessica is at the top of the stairs of the basement, still in the nightdress she burned to death in, one hand outstretched. "Sam," she says, but for the first time she doesn't ask why, only when—when are you going to stop destroying everything you touch, everything you love, and everything that loves you—and Sam doesn't have answers (he's never had answers for her, only regret), but he thinks he has a purpose, now (douse that horrible fire that was burning down the last of his resistance), and so he keeps going.

It's daylight outside of Bobby's basement, and it stabs into his eyes like knives. He leans heavily against the wall as he walks down the corridor, leaving a trail of red among the browns and yellows and blacks that sort of meld into each other without warning. He can feel (his) presence right behind him, and when he steps over and around things he can barely see and staggers on and on, he thinks it is only because of (his) guidance.

"I only want to help you, Sam," (he) says, over and over and over, "To help us."

Suddenly he feels somebody in front of him, clutching at his biceps, shaking him, shouting in his ear. He blinks furiously, and Dean's face comes swimmingly into focus. "Sam," he's saying, the word stretching and distorting until it's a barely recognisable sound, which is odd, because Sam can hear (his) voice crystal-clear and it's urging him to keep going.

"Sam, please," Dean says, and his voice breaks at the end of the please in a way that's nothing but sadness and regret and disappointment, and Sam can't take it anymore, he really can't. He swallows more blood, rears back a fist and hits Dean as hard as he can. As Dean falls, more hands come up to stop him, but he throws more fists, feels the satisfying smack of flesh and bone under his knuckles, and he keeps running.

He runs, and Lucifer runs with him.

"An angel."

Dean took a swig of the beer Bobby'd just handed him, hoping that maybe, just maybe, when he put the bottle down, he'd be back on that park bench, waking up after being slipped some demonic-scale mickey. But no dice—he was still standing over Bobby's kitchen tale, where Bobby'd just told him that the constipated tax accountant in the trenchcoat was an angel—an honest to God angel—that'd just pulled him out of hellfire like he was a human-shaped lump of marshmallow.

"I know it's a lot to take in at once," Bobby said, "but a hell of a lot's been going down while you were—well, not here."

"Which included a Biblical Apocalypse, right," Dean said, nodding. "I'm still not terribly enlightened, here."

"It has been written," Castiel intoned, "that when the sixty-six seals are broken, Lucifer will walk the Earth, and he will bring its end with him." He looked at Dean with the sort of gaze somebody else might call 'piercing', but Dean? Yeah, he was still leaning toward 'constipated'. "The sixty-six seals have been broken. Your world is on the brink of destruction."

Dean licked his lips, settled down in a chair. "Now—I'm not exactly an expert on these things, but if Satan's out of the Pit, shouldn't something, I don't know, be happening? I mean, yeah, the world's a shitty place to live in, but I haven't exactly seen frogs falling from the sky or oceans boiling over, y'know?"

Bobby began to look uncomfortable for the first time since the conversation started. "It's a little more complicated than that. Dean—"

"Your brother broke the final seal," Castiel cut in, and now there was rage in his eyes, an ethereal light coiling and twisting somewhere deep within, and for the first time Dean thought he could believe that Castiel was a being with the kind of power to level whole cities in seconds. "He brought Lucifer out of his Cage—and into him."

Dean snorted. "What?" He laughed, looking from Castiel to Bobby, but the latter was grim, even fearful. "No way. You're shitting me."

"I do not understand this denial," Castiel said, sounding frustrated. "You saw your brother. You saw... what he is, the kind of state he's brought himself to."

(please i'm sorry let me go there now)

"It's Sam," Dean said bluntly. "I don't know what's with him right now, but—"

"Sam killed Lillith, Dean," Bobby said. "Killing Lillith was the final seal. The bastards had it all planned out—Sam used his demon-mojo, hunted down the bitch, killed her... and popped the goddamn devil outta his cage as a result." He leaned forward, gripping the back of a chair hard enough that his knuckles were white. "Lucifer's... inside Sam, right now. Crammed in the back of his mind like some sort of parasite. Once Sam loses control... once Sam says yes... Lucifer takes over. And the whole world goes to shit."

Dean kind of wanted to shoot something—preferably the bastard in the trenchcoat—like never before in his life (if i become something i'm not), damn the consequences (you have to promise to kill me). "Is that—is that why he's—"

"That's withdrawal," Bobby told him flatly. "At least that's what we think it is—see, Sam was chugging down demon-blood to fuel his... power, whatever you want to call it. It was—" Bobby shook his head. "It was like the worst kind of drug, Dean. He was—we had to lock him up."

Dean looked at them for a long moment, then started laughing. If there was a hysterical edge to his laughter, well, he felt pretty damn entitled to some hysteria after being resurrected by a freakin angel and told that his brother was a demon-blood junkie who just set Satan free. Speaking of which—"Demon-blood? Really?" He strode over to pull out the handgun he knew Bobby stored in a small cupboard right above the stove. "Look. I don't know what kind of bullshit this bastard's been feeding you, but from what I can see, Sammy's really, really sick, and you're freakin locking him up in a cage like an animal." He levelled the gun at Castiel.

Bobby... seemed remarkably unconcerned. "How else do you think you're here, Dean? Castiel—"

"So tell me," Dean growled, "why did you bring me back, huh? Why now? Why not stop Sam before all this went down?"

"You were brought here," Castiel said, "because God commanded it. Because you can stop the Apocalypse, Dean. You can stop your brother."

Dean pulled the trigger.

The bullet went into Castiel's forehead. He seemed completely unfazed, however, and the bullet squeezed itself out and clattered onto the tabletop, covered with what should be bits of Castiel's brain. The grotesque wound closed itself.

Dean stared.

"Dammit, Dean! Of all the trigger-happy idjits to ever come here, you Winchesters—"

"Every word I say," Castiel said quietly, "every action I take, is God's will. Nothing in this world can kill what your brother's become—except you, Dean. That is why you've been brought here."

Dean hadn't really processed everything—was in no state to process anything, ever, except are you sure this is one hundred percent pure Sam and he will lead our army running through his mind, over and over again—when they heard noises from behind them. Dean turned to see Sam stagger to the kitchen doorway, trailing blood and looking more like a zombie than any of the zombies that Dean had ever seen. There was blood dripping in great thick globs from his mouth and chin and nose, eyes bloodshot and crazed, and he was swaying on his feet, looking as if he was going to fall over any second.

Dean didn't waste any time. "Sam!" He grabbed at Sam's arms, tried to keep him upright. Sam didn't seem to be able to focus on him, though—his pupils were pinpricks, and the heat radiating off him was unbelievable. "C'mon, man, don't do this."

Again Sam's eyes finally rested on a point somewhere above Dean's shoulder, and his face contorted in a weird mixture of relief, fear and rage. "Need... to go..." he said, pushing awkwardly at Dean, trying to break free.

"He needs the demon-blood," came Castiel's voice, low and even and quietly repulsed, and Dean couldn't fucking take it anymore. "Sam, please," he said. Please don't be who they say you are.

Sam jerked in his hands, suddenly focussing on Dean. But they couldn't really count this as progress, though—for, the next moment, Dean's vision was filled with the sight of Sam's bloody knuckles. There was a sharp burst of pain across the side of his face, "Dean!", and then darkness.

Sam had spent two hours staring at a bloodstain on his jeans in a dirty motel room in Madras, Oregon, when his brother walked into the room. Dean didn't say anything, just sat on the bed across from Sam (Sam had asked for two beds out of the force of habit—or maybe because of that little part of him that refused to be crushed that kept saying Dean would come for him) and they spent a few minutes in silence.

Dean was the one who hated uncomfortable silences, so Sam surprised himself by asking, hoarsely, "How did you find me?"

Dean rolled his shoulders and looked away, like Sam'd just asked a stupid question, and Sam figured that, yeah, it was a stupid question. Dean knew him scarily well, and even after everything, that probably would never change.

"You left a trail about as wide as the Pacific Ocean," Dean told him dryly. "Just had to find the nearest site of demonic presence and ask around for a bloody maniac."

"Oh." Sam looked down at his jeans again.

A few more minutes passed before Sam dared to look at his brother. There was no anger—not yet, not like he'd been expecting—just exhaustion. And disappointment. That hurt worse than any angry barbs Dean could've flung at him, but Sam probably deserved it.

It had occurred to him, while draining a second demon of its blood, that this was the Sam Winchester that Dean had come back to, that he was now one of the creatures that Dean would want to corner and kill like some nameless, faceless monster. He didn't want to think about what it said about how far he'd fallen that he'd just continued drinking.

"Castiel says he's under orders not to touch you," Dean said. He laughed hollowly. "Angels, man. And you?" He shook his head. "Goddamn worst week in my life, and that's saying a lot."

"I'm sorry, Dean."

"Yeah, whatever," Dean said, and looked away.