A/N; This idea is yet another of the things to randomly pop into my head. Sam drank demon blood. What if he went the other way and took a hit of Angel Blood?

The real story starts during My Bloody Valentine in Season 5, but, before that, I have a sort of recap thing set up to make the whole thing flow better.

Anyways, on with the story.

Chapter 1

Blood

The blood.

God, Sam hated it. He hated it, and he loved it at the same time. Ruby. He loved her, and he hated her, at the same time. She made him into this, she gave this to him. He'd made the choices, but she'd layed out the cards. He hated feeling the blood poor down his throat, but he'd be a liar if he said he didn't like it, like the way it felt, liked what it did to him, the power it gave him.

Lilith killed Dean. She made him a hellhound chew toy. That's how it started, why it started. Kill the snake. Kill Lilith, the Queen Bitch. That's how it started, oh so long ago. How the blood drinking started. He loathed himself for it. He felt filthy. But, he'd already lost it all, so what was the point? He wasn't planning on surviving anyways. Once Lilith was gone, dead at his feet, he was going to join Dean in Hell.

At least, that was the plan. At first, that was the plan.

Then the angels. Then Dean coming back. All hell breaking loose. His powers. He honed them, for Dean. Always for Dean. Dean hated it, he freaked, went wild. He was scared. He was scared Sam was going to go darkside.

But Sam wasn't going to go darkside. At least, that's what he kept telling himself.

Dean's presence, it was enough. Enough to keep him from surrendering, fully surrendering. True, Sam became a demon-blood junkie. But he never gave into his powers, not truly, not fully. If he had, demons wouldn't have been is only victims. If he had, he's have been a threat that even an angel would have trouble taking down. That's why they didn't 'want him' using his powers, initially.

All just a rouse.

They wanted this, those bloody angels. Angels and demons, both of them, both sides, manipulating the pair of them. And Sam and Dean? Too blind to see. Too locked on trying to save the other to actually realize what was happening all around them.

Then, bang.

Castiel tries to stop it. He figures out what the hell's going on. An angel dies in the process, an old friend of his. Lucia. She found out what they were planning, what was really Heaven's endgame. And she tried to stop it. She managed to warn him. It cost her her life.

But he wasn't fast enough.

The angels took him, ditched the body, and took him up to Bible Boot-Camp. Maybe if Castiel had been stronger, just maybe... But he wasn't. He hadn't been feeling for very long. Emotions were a thing new to him, and, because of it, there was little resolve.

And what little resolve was there was shattered by the might of the Archangel Raphael, who personally oversaw Castiel's restablishment among Heaven's Finest. After all, he was one of their greatest warriors. There was a reason Castiel was so emotionless compared to the rest. After all, how many of his own brother's had he slain in the war against Lucifer, all those years ago? How many fallen angels had he felled? He had hated it then, and he hated it now.

But he was a good little soldier again, right?

But the human. Dean. Dean, Dean, Dean. Somehow, Dean get's to Castiel. Somehow, Dean's pathetic struggle and endless resolve to never give up motivates him, influences him. Even as he see's the bond between Sam and Dean begin to shatter under the stress they are slowly putting onto the brothers, the way they would give anything for each other get's to him. The brotherly bond, the strong roots of family- what Castiel had once had, before the war, before Micheal ordered him to execute his own brother, his twin, and after he had followed through with that command. He still remembers Dumah's blood, falling endlessly. Remembers cradling the other in his arms, before he is snapped at for showing the pathetic human weakness known as feeling.

Not that he'd have the brothers know that. There are some aspects of Castiel's past that he'd much rather forget.

Then, the angel turns. He becomes a rouge, like so many others before him. Like the so many others he was ordered to hunt, strike down. He becomes a Fallen Angel. For Dean. For Dean, and for Sam, because, for the first time in a very long time, he has hope. He has hope, and they give it to him.

They fail.

Dean doesn't get there fast enough.

Sam, hyped up on demon juice, not caring that he's turned himself into a monster, a freak-because it will save the world, and, more importantly, Dean- kills the Queen. That's when Ruby reveals herself. She tells him what she's done, what she's tricked him to do. Sam, broken and betrayed by the demon he had come to love, hate, and trust, turns on her.

He can't kill her.

She lies about the reason why.

Dean breaks down the door. They stab her, with her own knife. A knife she made from her own soul, so many centuries ago. That's why it kills demons. Because it's made of soul energy. Fueled by the immense power found within that the pathetic life forms that scour the earth- humans, and the endless power within their souls.

Lucifer's free. After all the effort to toss him down south, the fallen Archangel is free.

And the Apocolypse, in all it's gooey chaos, has begun.

Horsemen everywhere, signs of the Apocalypse raining down, and at last, this.

Famine is the one that does it.

Sam craves like he hasn't craved since the height of his addiction. He fights it, for Dean. Even as everyone else around him succumbs to Famine, he fights it. For his brother. But, it becomes strong. Too strong.

They chain him up.

Famine sends a gift, and little Sammy breaks.

He tracks down Famine. That's were Dean's gone. He has to rescue Dean.

The look in his eyes when he see's the blood running down his brother's face. Maybe if Sam hadn't been hyped up on the blood, the look would have killed him. But he knew what he had to do.

It was so much harder, standing before Famine himself. He could hear the blood pumping through the demon's veins. He wanted it. More than wanted, needed. Like nothing else existed but the blood. But one look at Dean, at Castiel, fallen and on the floor, mouth stuffed of red raw meat, Sam knows he can't.

He fights it.

For Dean.

Always for Dean.

Famine can't die. Sam makes him wish he could.

Then, they lock Sam up, in that room, all over again. He's screaming. Over and over. Pleading.

"DEAN! Dean, please! Help me! Please, help me! Help me!"

Dean closes his eyes. He stands outside the door. He wants to break it down. Sammy needs him. His Sammy needs him. His little brother needs him.

But he can't.

All he can do is listen to his brother's tortured screams, and, like the masochist he is, he doesn't leave.

"Dean, Cas! If you're right there... Please, please! No, no! STOP! NO, NO!" the cries continue, over and over, filled with anguish, filled with torture. Dean's only heard sounds like that one time before.

When he went to Hell.

What he doesn't know is this; Sam was gone two days. Gone two days here, down five months south. Sam had been to hell. He'd been there, and the Crossroads Demon, she took that little memory away. But the demon blood, when Sam fought it like this, it made him remember what happened down there. All the suffering he saw. All the confusion.

He didn't remember everything. He didn't remember the details, which were foggy at best. But he remembered pain. Pain, and suffering. The safe suffering he inflicted upon demons with his mind was being inflicted on him, a thousand times over. Agony so pure that within seconds Sam had even Alistair, a demon tens of thousands of years old, broken, shattered, spilling it all, confessing it all.

And now, it came down on him, over and over and over.

Why wasn't Dean there?

Why wasn't Dean there to help him, to take care of him, when he needed him most?

Sam was lost in the pain. It was too much. Too much, and he was lost. Just lost, not knowing where he was. Not knowing a damn thing.

So he screamed. Again and again and again.

"Guys, help!" Sam cries. Dean can't do anything. He just raises the beer to his lips an takes one good long sip.

"That's not him in there." Castiel lies. It's Sam. They both know it's Sam. Hurt, broken, and weak Sam. But the lies, meant for comfort, are meaningless. "Not really." that part is true. It's Sam alright, but, right now? The Sam they know is lost. Lost in his own mind, suffering under such degrees of mental torture that its a wonder he still has any sense of sanity left after it all.

"Dean, Dean, please!"

"I know..." Dean whispers. There's no emotion on his face. He doesn't want to feel, not anymore. He doesn't want to go on. After everything, after all the hell, now this? He was to listen to this again? A part of him has a nagging suspicion Zachariah was behind all this, that the Seraph somehow led them to Famine. Why? For Sam to crack, and for the relapse to break them both.

Because those screams in there?

Dean would rather be back in Hell than to have to hear them ever again.

"Dean, Sam just has to get it out of his system." Castiel tires again. Trying to sooth the other, over the screams of the broken. "Then, he'll be-"

But Dean doesn't let him finish.

"Listen, I just uh..."

"Deeeeeeeeeeeeeaaaaaannnnn!"

"I just need to get some air." then he turns to leave. He can't hear those screams. He can't. It just hurts too much.

Castiel hesitates. He knows its risky, but... For Sam, and for Dean, he's willing to try. "Wait!" Castiel calls.

"Cass, just please, drop-" Dean's voice cracks. He's practically begging.

"I might be able to... To help him." Castiel's voice is but a whisper, but Dean catches it. He wheels around, eyes wide.

It seems to good to be true. But there's honesty shining in the blue orbs of the rouge angel. Honesty, pain, hope, and, though Dean doesn't catch it, just a touch of fear.

"How?" Dean asks. His voice is nearly drowned out as Sam gives yet another broken yelp. At this point, Sam can't even form words anymore. The screams are starting to lessen, but not because he isn't in pain. No, they're lessening because his throat is growing hoarse, his lungs aren't working properly, and the pain is literally killing him.

"Dean, I don't- it could be risky, there's no telling-" Castiel begins.

Oh HELL NO! Dean feels like screaming a bit himself too. He storms towards the angel, grabs him from the trench coat, and slams him up against the wall. "Don't you dare give me false hope, Cass, don't you dare!" Dean cries. He's on the verge of tears, but he holds back. "Can you?" the voice cracks again, a hundred times over. "Can you help him?" he whispers.

"I- I might be able to." Castiel nods.

"How?" Dean is pleading at this point, but he can't really bring himself to care as Sam hollers once more.

"Angel's blood is the opposite of demon's blood... Maybe, just maybe, if I... It might reverse the demon blood in his system." Castiel speaks.

Angel's blood? More blood for the junkie? Dean can't think straight, not with Sam like this, but he knows one thing. He can't stand Sam screaming like this for another second. And if this can save him, cure him, hell. "Please, Cass. Please..."

"Very well." the angel nods, reluctance yet determination shining in his eyes. He pushed Dean back a bit, then walks towards the door. He opens it, and Sam gazes up. The second he sees Castiel and Dean, he recoils, starts to whimper.

"No, not again... Not them, not them, not again..."

Dean feels something in him break.

Sam's hallucinating. He's hallucinating that his big brother, the one that practically raised him and always took care of him, is the one there holding the blade, making him make those noises, making him suffer like this. That damn blood in him is making him see things. It's making him believe that Dean would hurt him, that Dean would torture him, that he is torturing him. Something cracked in Dean as he saw that, as he witnessed it.

Alistair had done the exact same to him down in Hell...

Always changing. Mom, dad, Bobby- but mostly Sam. Sam, with Yellow-Eyes, taunting him that this is what he wanted and that this is what he was, and that he didn't want to fight it and that he was going to make Dean just the same as him.

Castiel looks to Dean, pulling him from painful memories. The angel looks scared. After all, he doesn't know what will happen, doesn't know if it'll work.

"Do it." is all Dean can say, his eyes never leaving the whimpering Sam, who tosses and turns, locked on the straps of the table, unable to move. Unable to escape like he desperately wants to.

Castiel nods and walks towards Sam.

"No, no! Please, stop! No, please... Please, PLEASE!" Sam's eyes are wide, pleading, emotion pooling in them. Dean can't look. Finally, he turns away, and the tears start cascading down his cheeks.
Castiel takes a knife in hand, and Sam reacts as expected. More screams. Kicks. Pants. Pleas. Castiel cuts a small wound beneath his wrist. Then, wordlessly, he places the wound to Sam's mouth.

The screaming stops and Dean finally opens his eyes, finally looks back. Sam, drinking Castiel's blood, his face calm, peaceful, in bliss. His eyes are closed with a look of ecstasy, his skin practically glowing. All because of the blood pouring down his throat.

It makes Dean want to gag and vomit. Makes him want to retch, over and over. Makes him want to pull Cass away, and give him a good smack for good measure. But, if it'll cure him, cure Sam, make the screams stop that torture him so...

Castiel takes the wrist, the blood, away, and watches as Sam's eyes open ever so slowly. He looks, for the first time in a long time, well rested. At calm. Dean face lights up in a way it hasn't in a long time. He's happy. Truly happy, something he hasn't felt in a long time, far too long. Sam is okay. Sam is going to be okay. True, he hates that it was blood, of all things, that healed Sam, but whatever works.

"Cass?" is the first thing Sam says, before looking up at his brother. "Dean?" he seems confused, like he doesn't know where he is.

"Sammy." Dean grins widely at him, even as he begins to free Sam, undoing the straps holding him bound. Once the last one is gone, Sam's eyes flash. Suddenly, he's up on his feet. Suddenly, with a small shove, Castiel is flung across the room, slammed against the wall.

"Sam!" Dean eyes go wide. Next thing he knows, he's slammed against the wall, a hand around his throat. Sam grins at him. His eyes flash again. White. Not demon-white, but angelic white, mixed with just the hint of blue.

"I'm sorry, Sammy can't come to the phone right now, leave a message after the beep!" the thing that looks like his brother taunts.

Then, Castiel is there. He grabs 'Sam' by the shoulder, pulls him back, tossing him back a few steps before Castiel takes a defensive stance before Dean.

There's an Angel's Blade in his hands.

"NO!" Dean shouts as Castiel charges. He tries to stab Sam, but Sam is faster. Sam is quicker. Soon, the weapon is on the floor. Soon, the angel has been flung. Dean tries to do something, but with a wave, Sam has him trapped and slammed up against a wall... Again.

Castiel swings. Sam ducks, grabs him, forces him to the floor before picking up the angelic weapon and holding it to his throat. Sam leans in, smiling. "Hello, little brother. Long time, no see." Sam says coyly.

"You... You're dead..." is all Castiel can manage with the hand around his throat, choking him, taking the breath of life from him.

The Sam thing shrugs. "Suppose to be dead." he corrects with a smirk. "But, looks like I'm still here. Time to die." he lifts the blade.

That's when Sam, the real Sam, starts fighting back.

"NO!" he shouts. The blade drops, he takes a few steps back, staring in horror at Castiel. Castiel rises, his eyes shining with intent. Intent to kill Sam. Or, better said, the thing in him. It needs to die. As much as Castiel hates it, it seems Sam has to go down with it.

Then, 'Sam' takes away the choice. A flash and a flap of wings, and he's gone. Dean drops from the wall, his eyes wide.

"What the hell just happened!" he demands, even as Castiel picks up his Angel's Blade. He closes his eyes. He doesn't know what to say.

All that can be said is this; Sam was gone. Sam was gone, and, somehow, he'd been possessed by an angel, and not just any angel. A fallen angel. An angel that was suppose to be dead. Castiel wondered how it happened, because it made no sense, even if he had fed the other blood.

And now, one of the most dangerous beings to ever walk the Earth was back, and wearing Sam like a prom dress.