Prologue

Sam sat in the bunker, staring at the floor. The events of the past 6 months raced through his mind, beating at his brain like a baseball bat. The Mark of Cain had overtaken Dean, Cas' grace was all but diminished and Sam was out of options. He had tried to find Crowley and force him to put back the broken pieces of his brother but, being the King of Hell, and now with Dean as his right-hand man, he cared nothing of Sam's request. Sam researched every one of Bobby's books, read every piece of literature that the Men of Letters had in the bunker and nothing provided him with any solutions; except one. Kevin had taught him how to cure a demon. The only problem was that if Sam cured a demon, he would finish the trials – which would likely kill him. No other hunter could possibly do it because, inevitably, they would kill Dean instead. Then of course was the issue – could he even be cured? Is the Mark too strong to be cured? All of these thoughts made Sam's head hurt and his insides burn with rage.

"It's been six months, Sam." Cas grumbled.

"I know."

"I don't think you understand…"

Sam erupted with anger, "What, Cas? You don't think I understand what? That my brother is a demon? That the Mark of Cain and Crowley have taken him over? That every day he spends as a demon, the less likely he is to be cured? How absolutely and utterly screwed we are?"

"How dangerous it could be to have one of the best hunters on Hell's side." Cas said calmly, but with gravitas.

Sam understood all of these things, but what could he do? There was no hope. The last time he and Dean had spoken, it ended with Cas securing Dean in a Devil's trap and using his fading grace to bring Sam back from the brink of death, which is where Dean had put him. Sam remembered the feeling of Dean's knuckles colliding with his cheeks, his boot across Sam's head and the look in Dean's eyes as he beat his brother to near-death. The lack of concern for Sam's life was evident and unfamiliar. Sam had nothing else to do but pray to an absent God for a solution.

Cas didn't see any other option. It wasn't about Sam. It wasn't even about Dean. Okay, it was a little about Dean. But mainly, it was about the fight between Heaven and Hell. Dean being a demon meant that Hell won. Cas couldn't, wouldn't, let that happen. He had to do this. Sam would probably be angry, but he'd come to understand. This may work to save Dean, but he'd never understand. Even if it cured him, Dean would hate Cas for this, but he had no other foreseeable option. Did he?

Chapter One

Anger erupted through Sam's veins as Cas explained what he had done. He was angry because Dean would never forgive him, if this in fact cured him. Cas should have consulted Sam before making such a reckless decision. His fist balled up at his sides, jaw clenched, he tried listening to Cas' reasoning but could barely see past the haze of anger.

"I don't care what you thought, Cas. Do you know how much of a setback this actually is? Not only do I have to deal with the emotional aftermath but I now have another person to be accountable for. I'm barely hangin' on here, Cas."

"I'll help. He'll need all the help he can get once he wakes up."

No sooner than the words left Cas' lips was another presence felt in the room. Sam whipped around to see another person staring awkwardly. He was tall, dark hair and he had her eyes. He was barely recognizable with his tired eyes and confused look. Sam didn't know what to do except wait. Wait for the panic that was sure to set in. Wait for the million questions he'd for which he'd have to find acceptable answers. Wait for the explosion of anger that was sure to follow. Sam used to be good at this kind of thing, but not with him. Not under these circumstances.

"Sam? What the hell is going on? Where am I? Who is the freak in the trench coat?" His eyes flicked with anger but mostly with fear.

"I can explain but maybe y-you should sit down." Sam pulled a chair out from the table and offered it to him.

"No! Tell me what's going on, right now. Am I being kidnapped? Where's Dean?" His hands were shaking and his voice cracked.

"That's kind of what we want to talk to you about. The….weirdo's name is Castiel, er, Cas. I really think you should sit down."

"I want to see Dean. I have questions for him, too."

Sam could see the desperation in his eyes and didn't have the heart to tell him about Dean, yet. Sam sat down at the head of the table. Cas sat next to him in hopes that their new companion would follow suit.

"It's been a week. Castiel, or whatever his name is, just left me there. He swooped in and did some weirdo magic trick on our brains and then left." Tears streamed down his face as he collapsed into a chair, his head falling into his hands.

"I know that getting your memory back had to have been a big shock…" Sam said.

"You think that's why I'm pissed? Really?" He looked at Sam and Cas, realizing that they didn't know what had happened after Cas had zapped their memories back in.

"It took them three days to find us. Casjust showed up while we were having dinner and touched our heads and all of a sudden all of these memories of Dean come flooding in our heads. Happy memories. It was confusing and my head felt like it was on fire."

"I know, trust me I do. When I got back…." Sam wasn't about to liken this to his return from Hell. He sat back, motioned for him to go on and listened; he wasn't sure what else he could do.

"That only lasted for a day or so. She started looking for him. Called his cell phone, tried to reach Dean anyway she could. To get answers, you know? But he never answered. Then, two days ago…" Tears welled in his eyes, though he tried to suppress them. His next words came out in a burst, more like a yell than a sob, "A demon killed her!"

Sam's stomach dropped. His eyes met Cas'. They both knew there who was responsible for this. The only demon who could have done this was Crowley. No low-level demon would have cared. Crowley knew the implications, though. He knew Cas' plan.

"How did you get away?" Sam asked, fervently.

"Luckily, I had all these great memories that had just come back and I ran into the kitchen for salt. I drew a circle around myself and waited. He just looked at me and smiled, then left. God those eyes…"

Sam couldn't imagine Crowley being scared of salt. If Crowley let him go, there was another reason for it. Sam's head was buzzing with information. He didn't know where to start. He was so angry at Cas, but he could tell that Cas was angrier at himself for not realizing this could happen. There was nothing anyone could say to ease the pain of the loss this young man had suffered. Sam knew what was in store for him. Revenge. Sam and Dean had lived this when their mother died. Every move they made was in connection with the way their mother died, the way Jess died, and now…now her.

"We're going to help you make this right, we are." Sam said, knowing this was of no solace.

"How? Are you going to bring her back?"

Sam looked over at Cas' whose grace was probably hanging by a thread if it wasn't already gone. He knew the answer was no. They all did. Sam explained that the only way they could help was to kill the demon responsible. That was their plan all along. That was why he was brought into this mess. That's why she died.

Sam explained everything. He started with Dean being a demon. This maybe would make the rest of it seem like a cake-walk. It took Sam hours to tell him everything about the last few years and what he had missed. About the Leviathan, Metatron, the war in Heaven and why Dean took on the Mark of Cain. After Sam was finished, they all sat in silence. Saying it out loud made Sam realize how crazy it all sounded. Cas' head hung in shame as he sat in silence.

"I know this is a lot to take in and we can't force you to help us." Sam said, "But we were hoping…"

"I'll do it."

Sam sighed heavily, unsure if it was a sigh of relief or contention, as Sam secretly hoped that he would say no, "Thank you. We'll get Dean back, ok?"

"I'm not doing this for Dean. Screw Dean. This is his fault."

"You're right." He was right. As much as Sam didn't want to admit it, and as much as it would kill Dean to know, he was right. "Then let's do it for Lisa."