I do not own Supernatural or any of its characters.

"Hello Moose."

"Bring back my brother" Sam requested angrily "or I swear you'll never get out of here alive."

"I can't bring him back." Crowley had a grin on his face.

"DO IT." yelled Sam.

"First you listen to me Moose, your brother is dead, well not really, not physically dead, he is not the Dean you knew." He still had that grin and Sam really wanted to tear his face apart from his body, what did Crowley mean by "not physically dead" ?

"Now do I have your attention ?" said Crowley looking at the youngest Winchester. Sam nodded, he wasn't sure what he was going to hear. "well, we all know that the tiny-would-be-god angel stabbed him and you brought him back here but you know Moose, Dean was the same as Cain, he accepted his death but the mark never quite let go."

"What do you mean by never quite let go ?" Sam was trying to figure out what the King of Hell was telling him.

"And I thought you were the smart one. The mark didn't let your brother die Moose, at least not entirely."

"If he is in Hell bring him back ! NOW !"

"Oh he is not in Hell but after I'll tell you the rest, you'd wish he was." Crowley's smile grew wider on his face. Sam didn't like it, he didn't know what was going on. "He became what he always feared to be Sammy. He is a demon."

"What ? No, Dean wouldn't let that happen !" Everything was blurry, Sam started to feel the alcohol in his body and began to wonder if Crowley was lying or telling the truth.

"How do I stop him ? Dammit Crowley !"

"The only one that can help you would be Cain and, sorry Sammy, but I'm not risking my sweet life over your newly demon brother." Sam was upset, he could tell that the King of Hell wouldn't help him to find Cain. Maybe Crowley was playing him, it wouldn't be the first time.

"How can I be sure you're telling me the truth ?"

"You're doubting me Moose ? After all we went through, I'm disappointed, really, I thought we were besties, amigos. Anyway, I'll let you process all those informations, I have a Hell to go back to. Bye bye." And he disappeared as fast as he came.

Sam couldn't believe what Crowley just said, no he really couldn't believe it. He ran to Dean's room, screaming his name, hoping for an answer but nothing, Sam arrived to the oldest Winchester's room only to find an empty bed, a smell of sulphur and no one to talk to. What could he do ? Call Castiel ? The angel already had enough on his plate but Sam knew. He knew Cas would do anything for Dean and that is why he must give it a shot. Sam hurried to the main room praying for Cas as hard as he could, maybe his friend would hear him, Sam didn't know if the gates of Heaven were once again opened but he had faith in the angel and if someone could pull this off, it would be him.
So Sam prayed, he prayed to his friend, he prayed to God, he even prayed to Gadreel, the only thing he wanted, was an answer or even if it was to say "we heard you but we can't help you", he would understand and he was desperate. Long after Sam began to lose faith and while looking through all the books he could think of, a voice arose behind him.

"Fear not Sam Winchester, for I have come on Castiel behalf."

"Where is Castiel ?" Sam already had his angel blade, ready to strike.

"He is busy rebuilding Heaven. He wants you to know that he heard your prayer."

"I need to talk to him, not someone else." Sam didn't want to talk to Hannah, he didn't trust her.

"CASTIEL IF YOU CAN HEAR ME, I NEED TO TALK TO YOU, NOT ONE OF YOUR ANGELS."

"I assure you Sam, you can talk to me." But Sam kept ignoring her, she is not the one his brother spent half of his time talking about, Castiel was the one.

"CASTIEL I NEED YOU BUDDY, IT'S ABOUT DEAN." At the mention of the name, Sam heard a feathery sound behind him, he turned around and two angels appeared. One wasn't someone he knew and the other one was Cas.

"Cas I need to talk to you, without your friends. Please."

"You can go, I'll call you when I need to go back." Cas was talking to the angels, whom in a second were gone. "I am so sorry Sam, Metatron told me, I don't know what to do anymore." Sam looked at Castiel and saw the painful expression on his face. "Heaven needs to be rebuild but I just want to stop, I want to see Dean, I can't do anything and none of the angels seem to find his soul." Sam understood at that moment that Cas wasn't ignoring him, he was searching too.

"Listen Cas, I talked to Crowley." Sam took a deep breath. "and he told me that the Mark of Cain wasn't ready to let go of Dean." Cas had that I don't understand face that Dean made fun of so often.

"He became a demon Cas. A demon."

"Are you sure Sam ? Where is his body, I need to see it."

"Not here, I brought him back when he got stabbed, I summoned Crowley and then I went to see if what he said was true. When I got to Dean's room he was gone."

The angel was trying to handle the news and what a shock. Dean, a demon ? He couldn't believe it, it was impossible, inconceivable. "Cas ..." Sam's voice interrupted his train of thoughts, "what are we going to do ?"

"I don't know, I can't go back to Heaven, not with Dean like that. Dammit Dean."

"Crowley said that Cain could help us but ..." Castiel looked at Sam and spoke before Sam could finish his sentence.

"No Sam, we can't ask Cain, he is a demon, he killed Abel, he is an abomination."

"But we must do something, Dean is going to be lost, it's my brother we're talking about !"

"Do you think I don't know that ! Sam, I've risked everything for him, more than once ! Don't ever think I wouldn't do it again." Castiel's eyes began to tear up, the angel didn't know what to do. Dean, his Dean, the man he gave up an entire army for became a demon. Maybe Sam was right, Cain could be the only option.

"Listen to me Sam. I will ask the others to look for Cain but I won't be able to approach him, he is even more powerful than Crowley, if we find him, you will be on your own."

"I get it, I'm ready. I'm going to pack." Sam turned around and went to his room thinking of what could be waiting for him, what could happen to his brother, to Cas and simply stated that he was ready to do whatever it takes to bring back his brother. The one who saved his life more than he can't count and the one who sacrificed everything to be with him. Castiel made sure all was taken care of in Heaven and made a request, which surprised most of his fellow angels, to find Cain. After a while Sam came back to the main room where he found the angel seated at the table, mourning his friend.

"Cas ?" The angel jumped off his chair, he wasn't expecting the youngest Winchester to be there.

"Yes Sam ?" he said, wiping tears off his cheeks.

"How's your grace ?" asked Sam quietly, he remembered that his friend's grace was slowly burning out and he was worried.

"Don't worry." simply stated the trench-coated angel in front of him. Right at that moment Castiel stopped moving, Sam began to move towards his friend when suddenly the angel turned around and merely uttered "Cain".

"What ?"

"They found him. Come we have to go now."

Sam followed Castiel to the Impala and drove to the location given to him. It will be a long drive, maybe the longest they've ever done. The location wasn't that far away but the atmosphere in the Impala '67 was tense, it was different because Sam was driving it, Castiel was the passenger and Dean wouldn't even be able to touch it. The thought of Dean trying to touch the Impala, his baby, but not being able to do so because he was a demon made Sam laughed.

"Why are you laughing Sam ?"

"I just thought that since Dean is a demon, it means that he won't be able to get into the Impala or to even touch it, can you imagine how he would react ?"

It made Castiel smiled, a sad smile but still. "Indeed, it would be hilarious." And this was the only dialogue they had throughout the drive, sometimes Sam would glance at Castiel to see how he was. He seemed to contemplate the sky and his face was giving away his feelings, Sam could see sadness, grief but also anger and determination.

"I think we're nearly there Sam." Castiel pointed at a house emerging in the horizon. "Remember, I won't be able to enter."

"Yes, I remember, don't worry Cas, I'll get him to talk."

Sam brought Ruby's knife along with them, since Dean was gone with the First Blade, the tallest Winchester thought it could be useful. They finally arrived to the gates, Castiel could feel the power emanating from the house but he also perceived the sigils all over the house that prevent all sorts of supernatural creatures from entering the house. Sam parked the car and got out.

"Sam please be careful, if you feel that something is wrong, get out."

"I will." said Sam walking toward the house.

Then Sam proceeded to knock on the door. Nobody answered. He knocked again. No answer. Could it be that Cain wasn't home ? Did he know they were coming and set them a trap ? Suddenly the door opened by itself. Sam took a step back, should he enter or should he go back to the car and drive away ? No. They came here to save his brother and he wanted answers. He entered, knife out, ready to strike.

"Before you try to stab me with that thing, you should know that it doesn't work on me kid."

Sam jumped, he really wasn't expecting to hear someone. Where did that voice come from ?

"I'm in the kitchen if you are looking for me."

Sam rushed to the kitchen and stopped by the door. The man he saw wasn't what he imagined, he was fairly tall and charismatic, he had a beard and looked like he was in his 60s.

"Are you Cain ?" Sam finally asked.

"Yes and who are you ?" said Cain seated on a wooden chair.

"My name is Sam Winchester, I'm here about my brother, Dean."

"Ah yes, Dean, I remember when he came with that filthy demon Crowley. He wanted to kill Abaddon, how's that going by the way ?"

"Abaddon is dead. Dean killed her with the First Blade."

"So he made it. What do you want now ? A trophy ?" Sam could see that Cain was losing his patience.

"No, I want to know how the hell do I get the Mark off my brother."

"Well, if you're asking me to do it, I can't."

"What do you mean by that ? You don't want to or you can't ?"

"Both. I don't care what happen to your brother but the only one who can take it off is the one that gave it to me in the first place."

"And who's that ?"

"Lucifer."

What did Cain just say ? Lucifer ? The Lucifer locked in his cage ? The fallen archangel ? No, it couldn't be.

"Don't make this face Winchester, if you want to free your brother, Lucifer is the one you seek. Now get out, leave me alone and get your ass and your angel friend out of my property before I decide to kill you."After hearing those words Sam decided he had heard enough, left before the powerful demon changed his mind and went back to the car where Castiel was waiting for him.

"Did he tell something ?" Sam could hear a hint of hope in his voice.

"Dude, you're not gonna like this ..." taking a deep breath, Sam looked at his friend and finally said "the only way to free Dean is to find the one who gave the Mark to Cain."

"But God is nowhere to be found Sam !"

"It's not God, Cas ..."

"So who was it ?"

"Lucifer."

After hearing that name, Castiel became white, his expression switched from hopeful to desperate. Lucifer ? Why ? Why is everything so complicated ? Sam started the car and set out to the Men of Letters headquarters. They had to think this through, they couldn't act rashly and without any clue of Dean's whereabouts. The ride seemed even longer than the first one, none of them spoke out loud during the drive but they cogitated a lot, they had so many questions unanswered such as how will they open Lucifer's cage ? How will they catch Dean and keep him close ? Cain was immune to the knife, did it mean that Dean as well ? Will they be able to catch him with a devil's trap ?