This story is based on the events in episode 11x10, so if you don't want spoilers, you have been warned!

I just jumped straight into the meeting with Amara, so I'll give you some of the background for this..

It starts when Casifer, Dean and Amara have already met, in the middle of nowhere, for what will become the big battle to stop her once and for all. *"Cas" convinced Dean that he had a plan and that he needed to trust him, in order to get near Amara (it doesn't really matter now how he actually convinced him, be imaginative).

Ok, so here it is. Enjoy my first SPN fic. And please comment =]

Cas looked intensely at Amara.

"It's been a long time, hasn't it?" She said and smiled at him.

Dean almost missed the excited look on the angel's face. Confusion struck him when he finally noticed the weird tension between the two.

"What's goin' on, Cas? You know each other?" He paused for a second. "No, it can't be, 'cause you weren't even around when all that shit went down the first time…"

There was silence. Dean's eyes kept darting between them as they stared at each other, smiling. He couldn't figure out what was happening, and it bothered him, a lot.

"Ok, someone say something!" He burst out.

"He doesn't know who you are," She said, amused as she realized what was going on. Cas' smile only grew bigger, and Dean started to freak out.

"What do you mean? What does she mean?" He turned to his friend. "Cas?" He asked demandingly, but a bit worried. Cas' face changed, and there was something very familiar in it. But it wasn't Cas that Dean recognized in that face, though he still wasn't sure exactly what it was.

"Oh Dean…" He started. "I could've carried on with this game for so much longer – and it would have been fun – but I guess it's over now." Dean tried to understand what the angel was saying, but he already knew it in his guts. He had known it for a while now, but he kept telling himself that he was wrong and that Cas was always acting a bit strange, and Sam encouraged that notion.

"You are not Cas," he said in horror. The angel seemed pleased with the fact that Dean finally got it.

"Ding! I knew you'd figure it out – you know, eventually. Although, I gotta say, as his best friend I would have expected you to notice it waaaay earlier. I mean, we are so different, him and I. But, I guess I'm a much better actor than I thought," he said, and seemed to be impressed by himself.

"W-who are you?" Dean asked now cautiously, a trail of anger and suspicion in his voice.

"Can't you guess, Deanie Weenie?"

Dean's face went blank and drained of its color.

"Oh look, you guessed it, didn't you?" He looked happy.

"Lucifer," Dean said in a low voice. He couldn't move. He felt as if his entire body was shivering with the immense hatred for this being in front of him. He clenched his jaws and just stared at the space ahead of him. "Where is Cas?" he asked in a monotone voice, trying to keep his composure.

"That really doesn't matter right now," he said in disregard. "You do remember that The Darkness is right there," he pointed at the woman across from them.

"No," the woman joined their conversation, "this is interesting, I will wait." She seemed to be enjoying the turn of events.

"Dean… do you really want to be doing this now?"

Lucifer's expressions on Cas' face made Dean grow angrier by the minute, until he couldn't control himself any longer. He grabbed him by the collar of Cas' coat, while Lucifer kept calm.

"Listen to me, you will bring him back right now!"

The angel sighed. "Castiel let me in so that I could help you," he said, as if explaining to a child that you are doing something that might seem bad but it's really for your own good.

"He would never do that. He would never do something that reckless!"

"Tsk tsk tsk… do you not know Castiel by now?"

Dean suddenly realized that that was exactly what Cas would have done. If he had thought that it was their only chance to save the world, from something that they themselves had started… It was just like Cas to do something crazy without consulting with him and Sam. Dean had just hoped that the angel would know better by now, learn from his mistakes.

His grip on the collar loosened as his mind processed all of this.

"You see? You know I'm right."

Dean's eyes were fixed on the ground now, and he was deep in thought, but Lucifer didn't stop, "he is very enthusiastic, my little brother. I admire that. He knows what he has to do and he does it."

After thoroughly thinking this through, Dean finally raised his head.

"This isn't your true vessel," he started. "You can't stay in that body forever."

"No, you're right. But this is a special vessel, created especially for Castiel after his original one got blown up, so it has its perks. I think I can live comfortably in here for at least… 50 years. By then I'll probably just find me another fitting vessel," he shrugged.

He's bluffing, Dean thought. It can't be that easy or he wouldn't have tried so hard to get Sam to say yes.

"I know what you're thinking," Lucifer cut his train of thought. "If I have alternatives why spend all this time chasing Sammy. But you see, it never even occurred to me to steal one of my brothers' vessels. I love my family. I truly do." Dean doubted that. "But what can I do… Castiel asked me to help, I couldn't ignore my precious little brother's pleas."

"So you'll give him his vessel back when you're done?"

"Well… it's kind of my vessel now, isn't it? And besides, I always wanted to be roomies with my brothers, I think it'll be fun."

Dean's anger was suddenly replaced with pure shock. "He is in there?!" He kept his voice as leveled as he could, though it came out pretty loud.

"Of course, where else can he be? Oh," his happy expression changed into that of clearly fake concern, "you thought that he was safe back in heaven, waiting for his vessel to be vacated. Nope, right here," he pointed at his own head.

Dean was becoming even more anxious. Cas was stuck in there with Lucifer. A prisoner in his own body (or vessel, whatever). He had to get Lucifer out of there, but had no idea how to do that. He couldn't stab him with an Angel Blade, because it would probably kill Cas along with him. Just then he remembered that there was another issue – The Darkness. If Lucifer can destroy her – and he is alreadyhere – then maybe he should rescue Cas after the whole thing is over. He just prayed that nothing happens to his friend meanwhile. Dean wouldn't mind if Amara ended up killing Lucifer, but not while he was in his friend's vessel.

"If anything happens to him…" Dean started, but Lucifer stopped him.

"Hold that thought. I'm starting to feel that at this rate we're not even going to get to the awesome fight that we've planned."

"I didn't plan anything with you," Dean answered with disgust.

"I didn't mean you, you silly ape, I meant my new roomie. Speaking of the devil – and I don't mean myself," he winked at Dean, which gave him the chills, "I think he would like to talk to you. Maybe it'll get things going faster… You behave yourselves boys. Remember, I am here too," he smiled. "And make it quick. Ta ta!"

"Wait, what?"

"Dean," a familiar voice came out of the vessel, and Dean's heart jumped.

"Cas?" He approached Castiel quickly and put a hand on his shoulder. Looking into his eyes he could feel that his friend was back, at least for now.

"Dean, listen," he started slowly, but Dean already had his arms around him in a hug, which caught him by surprise.

"What were you thinking?" He asked, half angry half sad because he knew that Cas will be gone again soon. He broke the hug and looked into his friend's eyes again, both of his hands on the other one's shoulders. Cas wouldn't let the sight of his worried friend shake his confidence.

"You need to let Lucifer take care of this, he is the only one who can."

"Why didn't you come to us? There has to be another way."

"There was no time. And I don't think that there is any other way. This was my choice, and I still believe it was the right one." He saw the disappointment in Dean's eyes. "Let him do this, Dean."

"I guess we don't really have a choice now."

At that very moment, a great smile was smug all over Cas' face.

"I'm glad you see that now."

Dean realized what just happened. His friend was gone again. "Alright," he said, "would you get this over with already." He couldn't look at Amara as he said that. He was still confused as to how he felt about her, but he knew what was the right thing to do. Lucifer, on the other hand, looked overly excited.

"You hear that?" He called at her, "Your boy wants me to finish you off quickly."

"Your confidence amazes me," she said to Lucifer. "You know, the last time you had my brother by your side. Do you really think you are a match for me all by yourself?"

"I'll never know until I try," he returned her a smile.

In the middle of the fight Dean was knocked unconscious. Had he known it was going to be that grand of a battle he would have taken cover, a few states away from there. Although, he was so concerned about Cas that he probably wouldn't have left anyway. When he regained his consciousness he thought he had woken up in hell. The surroundings looked nothing like before. Where there were trees and mountains there was only flat and burnt surface. He couldn't imagine what happened between these two to cause all of this. Moreover, he wasn't sure how he had survived this, but that wasn't his main concern at the moment. His eyes scanned the area for the source of the destruction. He had to find Cas and make sure he was ok. The first one he noticed though was Amara, who was kneeling on the ground not too far from him. She had a few cuts and bruises that seemed to take some time to heal.

So Lucifer did manage to inflict her some damage, Dean thought, but where is he?

He got up to his feet and started wandering around the battlefield, focused on finding his friend, preferably alive. A few minutes later he spotted a lump on the ground quite far from him. He was just about to run and check it out when he heard her voice coming from behind him.

"I wasn't that badly hurt in a long time," she said. "He really is quite powerful. But your efforts are futile."

Dean slowly turned to face her, terrified by her words. If Lucifer couldn't take her out, what can they possibly do? He doubted that God was going to make a cameo all of a sudden and save the day.

"When will you finally accept that you cannot defeat me? And that you don't need to. I am not a threat to this world, Dean. I wish you would understand that." He had a strange feeling that she was the reason he was still alive right now, but before he could ask her she had already disappeared.

For a moment he had forgotten what he was doing, but then it immediately came back to him. Cas. He turned back to look at the big lump in the distance, and started running towards it. He didn't even care if it was Lucifer, he just had to make sure that Cas was alive.

When he got closer to it he could see that it was indeed Cas' vessel, that was now lying motionless at his feet.

However you looked at it, they had lost.

"Cas! Come on, man… Cas!" He shook the body as he continued to call out the angel's name, hoping to get some response, any response. And he did. The body that he held tightly in his arms began to shift, and a few seconds later he was staring into those bright blue eyes. Dean wasn't sure what to do. For all he knew it could be Lucifer in his arms right now. He stayed silent, anxious, waiting for the response that will tell him who it is that he's holding.

"Dean…" a hurt and confused voice told him that it must be his friend.

"Hey, hey!" Dean tried to get a very disoriented looking Cas to focus on him. "Look at me. Are you ok?"

"I… I think so."

"What the hell happened?"

"She- she was strong. Stronger than he remembered."

"Where is Lucifer? Is he… dead?" Dean asked, hopefully.

"Dead? No." Cas was struggling to find the words, and seemed to be still in shock and a bit confused. But Dean couldn't let this go and continued to question him.

"Is he in there?" He asked, slightly more quietly this time. When Cas didn't answer Dean held his head firmly to stop him from looking around in panic. "Cas," he tried to draw the angel's attention to him. "Where is Lucifer?"

Cas' eyes stopped darting around and he looked directly into Dean's eyes. "He ran away," he said, as if he only just now realized it.

"What do you mean 'he ran away'? When?"

"He saw her going for a big finish… and didn't want to be in the receiving end of it. So he just… left the vessel."

"I can't believe this. After all of this, he's just a coward. I mean, don't get me wrong, I'm thrilled that you and him aren't roomies anymore, but-"

"But now he's free," Cas finished his sentence, looking down in shame.

They both sat there quietly.

"Great," Dean finally said. "Now Lucifer's out, God knows where on earth – or in Hell – he is. And The Darkness is probably indestructible. We have managed to make the situation much worse than it already was." Dean buried his head in his arms and looked defeated.

"You mean that I managed to make it much worse," he heard Cas say.

Dean didn't want to have this conversation right now, and he couldn't look at Cas, so he just continued holding his head down and didn't speak.

"I'm sorry, Dean. My plan didn't work as I hoped."

"No Cas, it didn't," Dean answered, unable to let this one go, but still wouldn't look at the angel.

Cas just continued, trying his best to hide his frustration and shame. "Well, if Lucifer couldn't stop her, then it only leaves Him. We have to find him, there's really no other choice now."

"Yeah, well good luck with that," Dean said and got up to his feet. "Let's go. We gotta get back to Sam and tell him what's going on." He held out his hand to help Cas up.

Cas stood there for a second and then started to sway lightly, and Dean managed to hold him just in time to balance him before he fell down. "What-" he couldn't finish his sentence when he noticed a red stain appearing on the side of Cas' coat.

"When did that happen?" He asked worriedly, while opening the coat to get a better look at the injury.

"I- I guess it was… from the last blow," Cas answered, trying to catch his breath. "it must've gotten worse when I stood up."

"Why isn't it healing?" Dean asked, starting to panic from the horrible look of the open wound.

"Dean," Cas said suddenly, with a look of horror on his face. "My grace, it's gone."

"What do you mean 'it's gone'?" Dean was getting more and more panicky.

"I don't know why… Maybe Lucifer… had something to do with it, or it happened… during the fight… I don't know how I didn't notice until now."

"Alright, you just relax." He realized that they were still standing, and it couldn't be good for anyone with that kind of injury, so he eased Cas back to the ground.

It seemed useless to try and get Castiel to calm down while he himself was obviously not very calm. But he knew that if he moves too much it will get worse. Lying down didn't appear to make things much better though. Castiel's face became paler and paler by the second, and his consciousness seemed to be fading.

"Hey!" Dean called out and tapped on Cas' cheek. "Don't fall asleep. I saw this in a movie once, it's very bad if you fall asleep! Now, who do I call?"

"Dean," Cas said quietly, struggling to get the word out and keep his eyes open.

"Yeah, that's great, keep talking to me! I need a name, an angel that will come and help. Give me a name."

"Find… Father… He's… our… last…" His voice trailed off until it faded completely. His eyes remained slightly opened, but the life has left them, and he didn't move anymore.

Dean couldn't comprehend what just happened. This was his best friend, and an angel nonetheless. He stared into those lifeless eyes, and the world was gone. There was nothing left, only miles of burnt ground, and deafening silence.

Well, you know, in Supernatural death is not really all that final, so there is still hope :)