A/N: The Mark of Cain arc has fascinated me since "First Born" aired in S9, when we initially met Cain. I loved how Crowley himself appeared to fear Cain, to be victim to Cain's power. I knew Bad Things would happen when Cain issued his warning. But of course Dean, being Dean, was focused solely on the mission, as always, and once again threw himself under the bus. I've been watching avidly as the Mark slowly took him over and made him into something that he admitted he didn't want to be. And I've been insanely curious about how the arc will be resolved. The show will go in a different direction, I have no doubt, but finally, I surrendered to my own desire to speculate and extrapolate, and this is the result.

"Born Beneath An Angry Star"

He touches his forearm. Traces the oldest symbol known to man. Feels the raised flesh. It has been dormant for some time, but now it is rousing. He feels the echoes of what he had been, remembers the demand, the insatiable hunger, the power that altered a soul. He recalls when he had not been a demon. He recalls saying he could not live with what he was becoming. And so he had accepted that death would give him release, would relieve him of the need, the hunger. Death would provide freedom.

Death had, however, merely made him a new animal. Something worse than he had been.

It comes to him, now, that it is time. And he, being who, and what, he is, and knowing all that the Mark gave him to know, knows also where he must go, and what he must do.

"Going out," Dean had said, and Sam, in the bunker library, merely nodded. He'd seen it coming. Heard it, now, as his brother jogged up the steps, pulling on his jacket.

Bang-bang-bang. Boots against steel. And a powerful body massing somewhere around one-ninety, driving itself upward, and out, and elsewhere. Deserting his brother.

This time, it was all right. It was what Sam wanted. To be at home, and alone. For this task, it was necessary.

She wasn't a Taylor Swift fan, though she had nothing against the singer. Her musical tastes just ran in other directions: Bonnie Raitt, Adele, Ella Henderson, with a bluesy edge and kick to the vocals. But Swift was all over the radio and a few of her hits were stacked in the deck of the old jukebox parked in a corner of the bar.

Then he shouldered his way inside on a rain-speckled night and the Swift song, wholly unexpectedly, popped into her head, with all the bright sass of what was, as it turned out, ominous promise in the lyrics, with the punch of emphasis on 'knew' and 'trouble' and 'walked in':

I knew you were trouble when you walked innnn . . .

Oh, yeah.

God almighty, yes.

Bad boys got her every time. Even when she swore off them, took herself to task with a few f-bombs thrown into the mix in an effort to convince herself she meant the vow to swear off such men; and even if she actually meant it when she vowed it, and even if she succeeded at avoiding entanglements for a while, eventually someone walked through the door of her daddy's bar and all the vowing and the f-bombs and intentions were overtaken by a glance from under lashes, a darkness in the eyes, a tension in the mouth.

It wasn't criminals she responded to; she'd learned how to avoid the true threats. But the ones who were tough, who'd trained themselves to be hard in defiance of what their true nature might wish; or had been changed by circumstances beyond their control, by a life requiring sacrifice . . . well, that was different. She saw it in soldiers, she saw it in cops. She saw it in men who wielded authority even if outside of the bounds of war or enforcement of the law.

Bad boys were not the same as bad men. She'd learned it young, spending so much time in her daddy's bar.

Sam thought it likely Dean didn't realize, now that they had separate rooms in a massive installation, that his brother, whose room was around a corner a few doors down, was nonetheless fully aware that Dean did not always sleep, that he spent hours pacing the corridors. Because Dean didn't realize that for all of the worry he invested in his brother, Sam invested the same in him. And it was worse, now, so very much worse. Because the Mark of Cain was alive again, and it was scouring Dean's soul. Flaying his spirit. It robbed him of rest, of anything akin to peace, of the means to take a breath without thinking about in- and exhalations. To simply be.

It was a redundancy, Sam knew, to damn Crowley to hell. It was, he supposed, rather like putting a rock star on house arrest in a 5-star resort with no amenities denied, on someone else's bill, with hot and cold running groupies.

But damn him, he did. Because it was Crowley who had aimed Dean toward Cain, toward the First Blade; who had facilitated the moment when Dean, utterly focused yet again on saving people and hunting things, committed to the act that had nearly destroyed him, by taking on the Mark.

Sam, seated in the library at an hour nearing O-Dark-30 as he watched his brother pound up the steel staircase and walk out of the bunker into a rainy night, pulled his phone from a pocket. Pressed the screen as the dialer came up, marveling again at how very odd their lives were.

Exquisitely odd, when a man could speed-dial an angel at any time day or night.

And it ocurred to him to wonder if that meant their lives were complicated . . . or uncomplicated. Speed-dialing was itself uncomplicated. But an angel on the other end?

Sam didn't know. He just waited for the angel to pick up.

When Cas did so, when Sam heard the gritty depths of the familiar voice, he said: "He's worse." And, with excess calmness that he knew very well underscored fear, "We have to do something. Something else. Something more. How soon can you get here?" When the voice answered, then raised a question, Sam said, "I have a plan."

Damn near closing time. Three patrons left nursing their last-call drinks: a longhaul trucker at the end of the bar, about ready to take himself out to his 18-wheeler cab for a night's shut-eye; red-haired Jonesy in the back by the jukebox perched on a chair with Rikki-Sue in his lap. Rikki-Sue whose skin had seen better days before she'd taken to hanging out every night in smoky bars, knocking back too much alcohol.

Her daddy probably would have run Rikki-Sue out, were he still alive. He'd never cottoned to loose women. But daddy was dead and she ran the place now, and she figured Rikki-Sue was due a roof over her head as much as the next person, instead of hanging out on a rainy street corner. Jonesy had an old broke-down trailer a block along the road . . . his home hadn't been mobile in years. But he'd take Rikki-Sue back to it, and it would keep her out of the cold another night.

He came in on a breath of misty rain, the shoulders of his dark jacket sparkling with droplets. There was the minute pause, the quick sweep of a glance around the bar to check where customers were before he moved again, before he looked up and saw her behind the bar. She saw him register her gender, as they all did their first time through the door. This was an old watering hole, old-style bar, not like the upscale places hiring women bartenders to bring in an extra drink or two. You didn't often find young women manning the bar at a joint like this.

Loose jacket over a shirt she couldn't see in the dimness of the bar, jeans; and a quick glance down showed her laced-up leather work boots. He moved with a slight roll in his shoulders, arms loose and free. Cautious. Contained. Aware of his surroundings. She'd seen boxers move like that, boxers with broad shoulders and slabs of lats spreading the shoulder blades. Beneath a shirt and a jacket she couldn't see that in him, but was betting he was built that way, too.

She made a point of glancing up at the clock on the wall behind her, so he'd know he was pushing the 2 a.m. closing time. She saw his glance follow hers, saw the time register; saw, too, that he didn't care. He just came on, just slid onto a stool, and asked for draft beer along with a shot of whisky. And make it a double. Hell, make it two.

She smiled. Yeah, he'd knock them back before closing and order two more.

Here at the bar, the lighting was better. As she filled the big glass mug from the long-handled tap, she got a good look at the man.

"Hey, Jonesy!" she called, on impulse.

He broke off his mouth-on-mouth conversation with Rikki-Sue, back there by the jukebox, long enough to yell "What?"

She had to get Taylor Swift out of her head. That wasn't at all the kind of voice she wanted as an ear-worm just now, as she splashed whiskey into glasses in front of this man, with that face, that mouth, those eyes, and she could barely catch her breath.

"Ronstadt!" she called. "You know which."

And so he did, and he played it, and she waited for the chorus before she poured herself two finger's worth of the best whiskey in the place and raised it in a salute to him that was also invitation.

Linda's soaring vocals, clear as a bell.

You're no good, you're no good, you're no good . . . baby, you're no gooooooood.

She had the feeling, though, he'd be very good indeed.

In a bad boy kind of way.

"Yes, I've brought what you asked for," the angel said, "but this is foolhardy."

Sam smiled. In his head he heard his brother's version: "Have you got shit for brains?" But no. Cas merely suggested his proposition was foolhardy.

"We've done the research, " Sam said. "There's nothing here to be found. And it makes no sense, Cas. Why would the Men of Letters, so thorough, so painstaking, have no information at all about the Mark of Cain?"

"You think they've hidden it."

"Or destroyed it."

Cas frowned. "Why would wise men destroy knowledge? This very place is a repository of information."

"Or maybe the Mark protected itself." Sam rose, grabbed a beer from the small fridge, offered it to Cas, who declined. A twist of the cap and he sat down again at a table across from the angel. "He gets uber-focused, just like Dad did. It's an admirable trait, but also a dangerous one, and Dean can be dangerously stupid sometimes. Or stupidly dangerous. Either one." Sam shook his head. "He took on the Mark to defeat Abaddon, doing the whole self-sacrificing thing yet again, but I don't think he even asked how he might get rid of it once it had served his purpose."

"He did not expect to survive," Cas said. "To defeat Abaddon, yes, as he did. But Metatron? The odds were very much against him."

He went into the fire again. And this time he saved more than just a brother, but humanity as well.

Sam attempted to distance himself by being clinical so it wouldn't hurt. Though it always hurt. "But Dean's mantra has always been to accomplish something, or 'die trying.' So, he killed Abaddon, and 'died trying' to kill Metatron. He's back now, but Dean, being Dean, won't talk, yet it's also possible he simply doesn't know. He wants to be rid of it, knows it's affecting him, but we've found nothing providing any kind of answer. And you've said you don't have much knowledge about the Mark."

"I recall when Cain killed Abel," Cas said. "I recall when the Mark was placed upon him. But I learned of it later. I was elsewhere. Tending other business."

It had always struck Sam as wholly bizarre that Castiel could discuss pre-history as if all had happened yesterday. And that he could discuss it with Cas.

He smiled, briefly sidetracked. "Seven years."

Cas lifted his brows. "Seven years?"

"That we've known each other." Sam shook his head. "It's freaking weird, man."

"I don't understand the reference."

Sam's smile broadened. "Seven years since you came into our lives." He drank down beer. "Since an angel pulled my brother out of hell."

Comprehension was implicit in Castiel's eyes. "And now he experiences a different kind of hell."

Sam nodded. "And we need to figure out a way to pull him out of this one, too. So, this may be the best way to get the information we need." He drew in a deep breath, knowing he verged now on something that might be as dangerous as anything Dean had done. "That's why I asked you here. I figured I might need the insurance."

"And Dean knows nothing about this."

"No way, no how," Sam declared with feeling. "But I'm pretty sure the tomcat's on the prowl, so we'll have time." He placed the flat of his hands against the table, pushed to his feet. "Let's do this, Cas."

He had been a more tender lover than she expected. Oh, there was drive, there was need, and a certain amount of haste in the first dance, but she'd expected it when she'd looked into his eyes across the bar. What she hadn't expected was that he would rouse again so soon, or that he would make the second dance slow and sweet and exquisite and all about her.

Now he lay face-down, sheets tangled about his legs, arms thrust under his head. She turned onto her side, made contact at ribs and hip, ran the flat of her hand down his back, across a flank. She leaned close to his ear and softly sang the chorus from Ronstadt's hit. But she changed up the lyrics, replaced a single word.

"You're so good, you're so good, you're so good . . . baby, you're sooo gooooooood."

In the moonlight, she saw an eye open, heard the gritty tone that fascinated her. "She's got a helluva set of pipes on her, but I'm more of a hard rock kinda guy."

"So—not into Taylor Swift, I take it."

The sound he expelled was half grunt, half breathy, incredulous laugh. He rolled onto a hip, hooked an elbow against the mattress, levered himself up so his head was propped in his palm. "Do you even have any hard rock on that jukebox?"

She smiled, ran a finger across his chest. Stopped at the tattoo. "We could go downstairs and take a look."

"Or not." He caught her hand. "Or we could—"

But he broke it off abruptly, and he moved so swiftly she saw nothing but a blur as he sat up, clamped a hand over the inside of his forearm, and swore resoundingly.

"What is it?" she asked, startled.

He offered her no answer. Only clutched at his arm and stared fixedly into moonlight while the sweat broke out on his flesh.

Cuthbert Sinclair, before being summarily dismissed from the Men of Letters, had warded the bunker with spells and hidden sigils. All were impenetrable—unless someone on the inside, someone who was himself a Man, or a Legacy, opened the way.

Room 7B. Hidden behind walls, behind a façade of shelving. Behind a door that locked.

Consecrated iron had been set into the floor, forming the devil's trap. Yet another impenetrable barrier for demonkind. It was a weapon humans wielded, and so long as the outer circle wasn't broken, it served as a perfect containment of those who otherwise could not be contained.

Sam set out the candles. Filled the bowl with the makings of the ritual, the ingredients of power. It was a call, a summoning, an insistence that the demon must answer. Cas, being who and what he was, had given to Sam what was needful. Now Sam opened the way. Sam forced the issue.

He drew in a long breath, felt the tremble in it. But he proceeded. Dean was not the only Winchester who could be uber-focused, who could be so determined, so willing to do what was required to do, even when it suggested that he did, indeed, have shit for brains.

"That makes two of us," Sam murmured. "I guess it's genetic."

He struck the match. Lighted the candles. Steadied his voice and found the words in his head, the strings of sentences that Cas had taught him. Enochian lacked the dexterity and flow of Latin, but it was a far older language, one born of heaven itself.

Another match, struck. Flame dropped into the bowl. Light came roaring up, shooting high toward the ceiling. Sam shielded his eyes with an upthrust hand. It wasn't the blinding glow of an angel's true form, but something more focused, something contained. Angels were a lightstorm. Demons were lasers.

"Continue," Cas directed.

Sam renewed the chant.

He feels the call. The summoning. At first he is astounded. But he comes to know who it is, and what is being done, and why he is needed.

He doesn't disagree. In fact, he smiles. Because it suits him to go. It suits him to answer. In truth, it makes everything so much easier.

He can refuse. He has the strength. But he won't. He'll go. And now he knows the way.

"What is it?" she asked again.

He shook his head. He had no answer for her. He only knew what was in him, what he felt, what was sensed, bone-deep.

"I have to go," he told her, and began to clothe himself.

"But—"

Dressed, booted, he turned to the bed. Leaned down, clasped her head in his hands, kissed her briefly as if in benediction, not remembrance of intimacies. "I have to go."

He can refuse. He has the strength. But he won't. He'll go.

I know the way.

Standing back from the devil's trap, from the now-fallen, extinguished candles, the empty summoning bowl, Sam swallowed heavily through the constriction in his throat. "You're not—" he began, then stopped, cleared his throat. "You're not how I pictured you."

The man standing within consecrated iron fixed him with a hard, implacable gaze that nonetheless contained a spark of sardonic humor. "And just how did you picture me?"

"In—robes. Uh, otherwise. Than you are. " Sam paused. I'm not doing this very well.

"When your brother first met me, I was 'otherwise,' too. No robes. Just a beekeeper's suit, with a netted hat. Cognitive dissonance, I realize, but there you have it." He shrugged. "When you've survived as long as I have, you learn to adapt. To assimilate."

Sam still had difficulty voicing his thoughts properly. "I don't think you could ever assimilate."

Cain smiled. "True."

Sam drew in a breath to steady himself. The power of books, he reflected, of illustrations, of images. He'd experienced it before, the formation of a mental picture of how something, or someone, looked, based on an imagination fed by description, by art. Lucifer looked nothing like a man named Nick, as Sam had come to realize in the cage. Cas looked nothing like an angel. Crowley's meat-suit was wholly otherwise than one might imagine for the King of Hell. But those were vessels, not actual beings.

"This is you?" Sam asked. "Not a meat-suit?"

"A vessel?" Cain shook his head. "WYSIWYG. As God made me, so you see me. Though I am actually much older than I appear."

He didn't look young. He didn't look old. He was a tall man, a powerful man, an imposing man, with a shock of graying hair swept back from a bearded face, wearing clothing that was unquestionably that of a farmer, not a man written about in the Bible. But it was the eyes . . . the eyes were ancient.

And those eyes shifted from Sam, looked at Castiel. "An angel of the lord," Cain said. "I haven't seen any of you for thousands of years."

"There was no cause for you to do so," Cas said. "You are an abomination."

Sam winced. Yes, he supposed an angel would view it that way. But the baldness of the statement still made him uncomfortable. Cas once called me an abomination.

"I must say," Cain observed, "that I understand why the Winchesters fascinate so many of us who are, as you say, abominations. An angel at their call? The King of Hell? And the earth's first murderer?" Yes, Sam was correct; there was a spark of humor in the eyes, and a dryness in his tone. "Ohhh, the company you keep." And then his eyes met Sam's again. "Synchronicity is a fascinating thing."

At some point, Sam now realized, he'd lost control of the situation. Of the conversation. Or maybe he'd never had it. And maybe it was best to let Cain guide things for the moment. Because he had the feeling he needed to pick his way carefully to what was becoming, he sensed, a minefield. "Synchronicity?"

Cain inclined his head. "As Carl Jung would say, the 'simultaneous occurrence of events that appear significantly related but have no discernible causal connection.'"

Sam couldn't help himself. "You read Jung?"

"I read everything," Cain replied. "I have a lot of time on my hands. But in this case, there is a causal connection. Your brother." He smiled faintly, though most of it was hidden in the beard. "I summoned him. You summoned me. Synchronicity. And it will be a perfect storm."

Sam shook his head. He was out of his depth, and the waters were taking him down.

"The burden has been recognized," Cain continued. "The sacrifice, now understood, is too great. He's not what he was, is he?" The father of fratricide moved within the trap, kicked aside the fallen candles as if they profaned his presence. "I issued a warning. Dean did what he always does in such circumstances: he blew it off. And now? Now the price is acknowledged. Now it's comprehended. The Mark is bearing him; he is not bearing it. The Mark has its own mind, Sam." He shrugged, gaze unwavering. "It was a momentary madness, when I killed my brother. Perhaps the devil made me do it." Again, the glint in his eyes. "How many times have you tried to kill yours? Shall I count them for you?"

The memories, the grief, assailed him. Yes, he had done those things. An empty gun prevented it when Ellicott's ghost got into his head in the asylum, bad aim and luck when Meg possessed his body and let a bullet fly. Then there was Lucifer who, with Sam's hands, had intended to break every bone in Dean's body until he could not survive.

But Lucifer had not prevailed, and Sam smiled. "If you know about those times, you know all the times I have saved his ass."

"And now?"

"He'll die, won't he? The Mark will kill him."

"As it would have killed me, eventually," Cain agreed. "But then, when I tried to deprive it of its power, to take back self-control by killing myself, it didn't allow me do do so. Instead, it made me as you see me today." He spread his arms. "Abomination twice over. Murderer. Demon."

"I can't cure the first," Sam said, "but I can cure the second."

Cain's gaze was unwavering. "It's time for me to die, Sam. And now, finally, there is a way for me to do so. Someone who can insure it. Someone from whom I exacted a promise."

Sam was at a loss. He had no knowledge of what Cain and his brother may have spoken about. "What?"

Cas's voice. "He wishes Dean to kill him."

"No!" Sam said sharply. "I brought you here to find out how to get rid of the Mark, not to have my brother kill you!"

Cain said, "I killed my brother with the jawbone of an ass. I've killed thousands of others. But the Mark won't let me die by my own hand. I did try. It's what made me into a demon."

"But you gave the Mark to Dean," Sam said. "You're free of it. Why must Dean kill you?"

Cain yanked back the sleeve of his shirt. "Free of it? I'm not free of it." He displayed his left forearm, and Sam saw stamped into his flesh near the elbow the shadow of the symbol. "It's diminished," Cain said, "but there remains an echo. Residual effects. Muscle memory, if you will. It was made for me. And while Dean bears the active portion of it, I'm still the first host. You might say I loaned the car to your brother, but I still hold the title."

Sam drew in a trembling breath, needing so badly to make his way through the minefield. "Something has to be done. It's killing him. It's changing him."

Cain nodded. "It's time. I knew it before you summoned me. I told Dean I would call on him, and now I have done so. He'll come. He'll do it. He'll fulfill the mission. It's what he always does." He looked at Sam. "You'll need to summon Crowley."

Sam blinked. "What?"

"You gave him the First Blade, Sam. Unwisely, but you're human, and fallible. Now we need the Blade. It's the only thing that will kill me."

"This . . . " Sam began, then broke off. All the flesh stood up on his bones as the implications came clear. "This isn't . . . I don't think . . . " He turned to Cas. "If we put the First Blade back into Dean's hands while he bears the Mark . . . "

Castiel's gaze was locked on Cain's. "You must take back the Mark first."

Cain shook his head. "They're linked. He must bear the Mark for the Blade to kill me."

"No," Sam said sharply. "You don't know what he's like with the First Blade in his hands."

Cain smiled. "I know exactly what he's like with the First Blade in his hands. It's why I dropped it into the deepest part of the deepest of oceans."

"We can't—"

Cain overrode him. "We can. We will. We must. I've summoned your brother, Sam, as I promised him I would. Now you must summon Crowley."

He can't refuse after all. He hasn't the strength. He'll go.

Because now the Mark insisted, and something else, something more. Something that crept into his bones, sent a wash of heat through his body, formed a certainty in his mind. Something ruthless, lacking mercy, exerting utter conviction that he would answer.

Downstairs, he realized the jukebox had never been shut off. It played now, working its way through a vast deck of music. Oldies, he'd discovered as he drank at the bar and told her without words that they would go to bed. Oldies with a mix of some new stuff.

It was a male voice, husky, immensely evocative with the simple clarity of chords, the emotional weight of the lyrics.

Sting. "Fragile." And two lines that Dean suddenly recognized described his very soul.

He unlocked, pushed open the heavy door. The keys were in his hand. He left behind the bar, moved forward to his fate.

That nothing comes from violence and nothing ever could
For all those born beneath an angry star

Sam heard the voice behind him, that smoke-and-whisky voice with its English-accented vowels. "Oh, holy hell. Well—so to speak. I suppose that's an oxymoron."

He swung around sharply, saw the man. The demon. The King of Hell. "Why aren't you in the devil's trap?"

One eyebrow arched. "Come on, Moose, surely you can figure it out. You brought me here originally, remember? Dropped all the fancy warding to get me through your front door. You practically gave me a guided tour of the place. And you know very well that when you summoned me to make a deal for your brother's life, I was in his very room." Crowley spread his hands. "Besides, the trap's a little occupied at the moment, wouldn't you say?" His smile was faint. "Hallo, Cain. Welcome to the party." Then his eyes shifted to Sam. "We seem to be lacking one of the hosts. Where's your brother?"

But Cain broke in. "You have it."

Crowley mimicked confusion. "Have what?"

"You have it," Cain repeated. "I can sense it."

"Jesus Christ," Sam blurted. "You're walking around with it? On you? You told me you were going to hide it."

Crowley tipped his head back and forth consideringly. "Let's just say I felt a tremor in the Force, shall we? You must remember, Moose—Cain was a demon long before I was. He has certain—advantages—over me. When I felt your summoning, I also felt his. So yes, I do indeed have the toothy bits in my pocket." His voice hardened. "Where's your brother?"

"He's coming," Cain said. "Can't you feel it?"

Crowley slid hands into his trouser pockets, wandered his way into the room. "I feel a lot of things." Sam saw him lock eyes briefly with Cas. "So, my angel, it comes to this at last. Do you think he'll kill us both? Cain, then me? Or the other way around? He swore it, of course. But then -" And now he looked at Sam, "- so did you. The next time, you said. Well, here we are. You don't at the moment appear to be taking an active role in my demise. But in the meantime, I must say you're falling down on your duties as host. No canapes? No drinks?" Crowley advanced farther into the room, rounded the devil's trap that once had contained him, then stood near Cain on the far side of the chamber. "Wouldn't you like to serve an appetizer before we get to the main course?"

Sam heard the step. Felt the tension in the room rise abruptly, sensed the sharp, bright acknowledgment, the recognition, the comprehension that now the world would change, among the three men.

No, not men. Two demons. An angel.

And now, too, his brother.

Crowley smiled and half-sang the words: "Hail, hail, the gang's all here."

Crap, Sam thought. This was not part of the plan. Dean was not supposed to be here. Not with Crowley, who held the First Blade.

He looked at Cas. "You were right. This is foolhardy." Then he looked at Dean. "I have shit for brains."

What he said was automatic, simple reflex, and it came easily. "Always have, Sammy." What he thought was nothing at all like that. What he thought was complex, complicated, frightening. "Was this your idea?"

"Part of it was," Sam said. "But—things kind of got away from me."

"No Plan B?

"Cas is Plan B."

The angel's brows lifted. "I thought I was insurance."

Dean watched the brief appearance of a dimple in his brother's cheek in a quick twitch of irony. "That, too." He drew in, then released a hard breath. "Dean—I'm sorry."

This, too, was reflex. "Always are, Sammy."

Crowley. Dean felt antipathy rise. It was sense memory, muscle memory. He and Crowley, hanging out like buds. Like besties. And it made him sick. But Crowley, at the moment, was inconsequential.

Cain. Cain was here.

Cain who stood within the devil's trap because, Dean was certain, he wished to do so. It was unlikely anything could hold a demon of Cain's power.

He saw the expression in Cain's eyes. The same spark of wry humor, but also watchfulness. I was a bug to him, before. A specimen to be studied. He let the demons inside his house just to see if I lived up to my rep.

That day, it hadn't mattered. Only the mission. But he had lived up to his rep, and it had given him two things: the Mark, and the way to the First Blade.

To Crowley, he said, "You knew all along. What I would become. You planned it. Didn't you?"

"Oh, I didn't know that you would die, Dean. That you would tangle with Metatron and get yourself killed. It was all about Abaddon. I was certain you would succeed in killing her, or I wouldn't have put my plan into motion. Cain would never have given me the First Blade, or the means to find it—but even if he had, I couldn't have borne the Mark. I lack certain . . . character traits."

He couldn't keep the anger out of his voice. "You've killed, Crowley."

"It wasn't about murder, Dean. You can ask Cain." His eyes flicked aside. "Hell, you can ask Cas. He told you once, I believe. That little bit of intel about a righteous man in hell." His smile was faint. "I was there, Dean. I saw your arrival. And I saw the look in Alastair's eyes. It was anticipation, but a little something more. Something Aretha Franklin sang about." And Crowley's raspy tone filled the chamber as he quoted the song: "R-E-S-P-E-C-T. You see, he couldn't break your father even in 100 years—and then that hellgate was opened and John Winchester climbed his way out. So he knew, did Alastair, that he would have to redouble his efforts when John's oldest boy arrived in our midst. Would have to be the best he'd ever been, to break you."

Dean recalled Alastair before him, chained to upright iron. Heard again the taunts. "Daddy's little girl broke in thirty."

But now he heard a different kind of truth.

Crowley's smile was faint, and there was a spark in his eyes as he spun out his story. "Alastair expected to invest perhaps a year or two in you, Dean . . . but no. Despite all his . . . significant . . . efforts, it took thirty. And that infuriated him. Where I come from, that qualifies as respect." He shrugged faintly. "Though admittedly the citizens of hell are not the demographic you were trying to reach."

Cain said, "It was a matter of worth. I told you that. But I told you, too, that with the Mark came a great burden. You were given an explicit warning, Dean. You chose not to heed it." He inclined his head, looked down at Dean's arm. "You have something of mine. Time I took it back."

It rose up with a clamor, burned like a flame. Dean sucked in a breath, yanked back the shirtsleeve, saw the blaze, felt the heat, and once again laid a palm tightly over the Mark of Cain, trying to relieve the bone-deep acid bite.

"You sonuvabitch," he blurted, and he didn't know if he meant Cain, or Crowley. Or even himself.

"You know what must be done," Cain said.

Cas sounded his own warning. "There is great risk, Dean."

Tightly he said, "There's always a risk, Cas. We're Winchesters." He looked at his brother. "Sammy, Sammy, Sammy—we really need to have at least a Plan C."

Sam affected a negligent shrug. "Why start now?"

Dean bent slightly, cradled his burning arm. "You sonuvabitch," he repeated, and this time he knew he meant Cain.

"It will only get worse," Cain said, "until you commit the final act. I called upon you, as I promised you I would. I call upon you now. See it through, Dean."

"You'll die otherwise, you realize," Crowley said. "I told you that. You're a human. You can't contain the power. You haven't felt like hurling because the Mark was in abeyance. Took a little break. But now . . . well, now it's time to go back to work. You made a contract with the man . . . and you know how I am about contracts." With a quick sideways glance at Cain, he reached inside his coat, then paused. "This isn't about me, Dean. Keep that in mind."

He took from his coat the jawbone of an ass.

Tossed it across the devil's trap.

Sam saw it in slow motion, saw it repeat in his mind like instant replay. The tumbling flight of the First Blade toward its intended recipient. Watched as his brother's right hand rose, caught, closed around the hilt.

Saw the lips draw back, the glint of bared teeth, heard the hiss of indrawn breath.

Saw, too, the flicker in the eyes. Green, then muddy. Then dark. Black-on-black eyes.

OhGodOhGodOhGod . . . "No!" Sam gasped.

Crowley's tone was deceptively lazy. "So, Moose . . . not quite enough purified blood after all." But his expression, his bland human expression, nonetheless indicated a very real concern. And Sam remembered that Crowley had described Dean even as demon as uncontrollable, and wanted above all things to keep the First Blade away from him.

He'd failed, Sam realized. Somehow, he hadn't completed the cure. The demon had merely been dormant.

Black eyes. Green. Black again. Dean radiated power. His body shook with it. He stared hard at the First Blade. His knuckles were white.

A quiver ran over his face. Teeth clenched. Muscles flexed in his jaw. Sam saw him lift his head, watched him look around the room. He judged. He weighed. His brother. Castiel. Crowley. Cain.

He could kill any of them. He might kill all of them.

Dean gone demon again, and the First Blade in his fist.

Sam saw the angel blade drop into Cas's hand.

Green/black/green/black. A roiling cascade in Dean's eyes, and neither color his own.

Crowley was amused. "A little confused, are we?"

Sam released the word on a rush of breath. "Dean." And inside his head, he said: Cas is insurance. Cas is Plan B. Hell, Cas is Plan C—

Because Plan A was screwed, so very, terribly screwed.

Cain's voice was clear. "Come ahead, Dean."

Crowley said quietly, "Pick a bloody side."

As deliverance stands before him with the First Blade in his hand, Cain touches his forearm. Traces the oldest symbol known to man. Feels the raised flesh. It has been dormant for some time, but now it is rousing. He feels the echoes of what he had been, remembers the demand, the insatiable hunger, the power that altered a soul. He recalls when he had not been a demon. He recalls saying he could not live with what he was becoming. And so he had accepted that death would give him release, would relieve him of the need, the hunger. Death would provide freedom.

This death, from a worthy man's hands, will be final. He will not rise again, neither as man nor demon.

Sam watched as Dean tilted his head one way, then another, as if he heard an inner voice, considered directions from a brain not his own. Sam believed he was running on sheer impulse, now, not thought. He was reactive, not proactive.

It was a litany in his head. Dean's still in there. He's still in there. He's got to be.

Cain said again, "Come ahead, Dean." And then he smiled. "As you so eloquently put it to me: 'Let's dance.'"

And it was a dance. A deadly, dangerous dance. Dean took a step. Two more. Then all the tension ran out of his body as the power uncoiled. Sam had seen it before, with Abaddon, as the impetus of a body drove it forward, extended the arm, closed the hand more tightly upon the First Blade. In two long strides Dean crossed the devil's trap and moved into Cain, stepped close, closer yet, and thrust the Blade through clothing, flesh, bone. Into viscera.

Blood broke from Cain's mouth, painted his teeth. He smiled a red smile as he closed his left hand upon Dean's right arm. "Be free of it," he said, and then he fell.

It was Cas, Dean knew. Cas standing close, so very close, echoing the posture he'd assumed in the hallway a matter of weeks before in order to capture a demon, to control him. Standing behind with encircling arms forming a prison.

Crowley's voice mocked it. "Castiel, really. You'll give credence to the rumors. And it's entirely unnecessary. There's no demon left in him now, happily for me. The little bits Sam didn't quite chase away are gone. They, like the Mark, have left the building."

"Let him go," Sam said.

Cas's voice. "Sam—"

"Let him go, Cas."

And he did, and Dean went down, went down hard to hands and knees as the breath ran loud in his throat.

The body lay close by. It was a human-shaped cinder. In one blackened, outstretched hand lay a splinter of bone, a scattering of teeth.

He was empty, and exhausted. He trembled, and felt like his bones might rattle right out of his body.

He also was himself. Wholly himself. Finally.

'Be free of it,' Cain had said.

Christ, but he was close, so close, to passing out. "A year," he rasped, and didn't recognize his voice. It was thready, parched, the unsteadiness of it akin to a rattle. "Like before."

Sam knelt down beside him, placed a hand upon his back. "Dean?"

" . . . a year . . . from the crossroads deal - to Lilith, and hell. And from the Mark . . . to now. Jesus, Sammy—I'm tired. Of it all. I got—I got nothin' left."

Crowley's voice came from very close by. "That's the thing about you, Dean. You give it all every time, every last bit of yourself, and then you say you have nothing left—but you always do. There's always—well, something more. It's what would have made you a splendid Knight of Hell. Of course, you probably would have killed me and taken over the place, so I suspect it's just as well you're back to being nothing more than an insignificant little human."

Dean sucked in a noisy breath. "You bastard, if I were just an insignificant little human, you wouldn't even be here. That's the last thing I'll ever be, you son of a bitch, and you damn well know it!"

Crowley touched the toe of his shoe to bone shards, to teeth. Scattered them. "That may indeed be true. But at least now there's no Mark of Cain upon you, and no First Blade. I suppose I can sleep nights now. That is, if I slept." And as Dean managed to lift his head, to meet Crowley's eyes, the demon presented him with a glint in the eyes that was of true humor. "I'll say goodnight now—or perhaps good morning is more appropriate. Time I left you boys to . . . well, you know." He waved a hand. "The bro-mo thing."

He didn't depart as a demon. He strolled out of the chamber, whistling a tune.

"I should have killed him first," Dean muttered.

"Come on, let's get you up." Sam hooked an arm under Dean's shoulder, levered him from the ground.

On his feet, Dean felt ridiculously weak. He wobbled, dipped, nearly surrendered to gravity as his knees buckled; was sustained in an upright position solely because his brother kept him there. His very tall, very strong brother, who'd left childhood far behind.

"It doesn't matter," Dean said, hoping he made sense.

Sam's brows arched. "What doesn't matter?"

"That you're taller than me."

"Uhhh . . . I'm clueless here, dude."

"Because I'll always be the big brother. That's age, Sam. Just age. Nothing to do with height or weight."

"Right."

Dean patted him on one shoulder. "But at this moment it's a good thing that you're taller than me, and heavier, because I'm about to do a face-plant. And I don't wanna. So how about you keep me from doing that, okay?"

Sam's brows ran up, then dropped down again. Dimples appeared. "Come on, big brother. Let's get you to bed. You can do a face-plant into your mattress."

"Do you need assistance?" Cas asked.

As one, the brothers answered, "Nah. We got it."

But Dean held back even as Sam began to turn him, to aim him. He looked down at the remains of what had been a man, before he killed his brother. "Sammy?"

"What?"

"Next time let me come up with the plan."

"I don't think so, Dean. Your plans usually consist of 'Don't die.'"

"Well, this was a shit-for-brains plan."

"Do you want to do a face-plant?"

"No. They hurt."

"Then shut up."

"Okay. But wait . . . wait, Sammy. I got somethin' to say."

Sam waited.

Dean knew he wouldn't be standing were it not for his brother's aid. And that was all right. For once, it was all right.

"I'm proud of us," he said. "I'm proud of you, Sam. Dad and I weren't very good at raising you, I know . . . but you found a way to grow up into one damn fine baby brother. Oh hell—a damn fine man."

Sam opened his mouth. Closed it. Tried again, and failed. All he could do was nod his thanks.

"And don't ever expect me to say anything like this again."

"No, Dean."

Dean closed a hand behind his brother's neck. Squeezed. "Okay. Okay."

He tried then to walk, but Sam pulled him back. Pulled him back, pulled him around, pulled him close, and wrapped him up in his freakishly long arms.

Dean's arms weren't as long. But they fit nonetheless. Where they always fit, when needed.

Castiel asked, "Is this a bro-mo?"

He felt Sam's laughter against his chest. "Yeah," Dean said. "It is."

And it felt damn good.

~ end ~

A/N: Well, if you've seen 10x12 "About A Boy," you now know that Dean is not opposed to listening to Taylor Swift. Ah well!