Summary:Tag to The Devil in the Details. AU. Lucifer has escaped and is currently wreaking havoc in Cas's body. Sam hasn't been seen since the Darkness was defeated by Lucifer, which was over two months ago. And Dean is desperately trying to fight the newly-arrived apocalypse. And the only way to stop the end of everything? Put the broken fellowship back together and have it rise up against the evil of the world. Can Team Free Will Rise once again?

Disclaimer: I don't own the boys. They were on my Christmas wish list, but no luck...Oh well. There's always next year.

Chapter 1: What happened that day

Washington D.C., six months ago

"Cas! What the hell are you doing?!" Dean yelled. Cas's blood was dripping from a cut on his hand, ready to complete the summoning spell. "Cas, you can't bring the Darkness here! She'll kill you! She'll kill everyone!" Cas shot Dean a sickening grin, and then Dean realized what he should've known all along- it's not Cas.

But Dean was not the one that freaked out. Sam stumbled backwards, a cold fear set in his eyes. "Not you," he stuttered in disbelief. "It-it can't be you."

But not-Cas was still smiling. "Good morning, sunshine. It took you long enough to figure it out." He chuckled like Sam had just told the greatest joke in the world. "I mean, seriously Sammy. And I thought our time together meant something."

"What have you done with Cas? Is he in there with you? Having two angels in one vessel can't be good for the vessel."

"Is this what we're talking about? The last time I checked the universe is ENDING!"

Dean looked at his brother, confused. Two angels? "What are you talking about? Sam, who the hell is this?"

It wasn't his brother that answered. "Oh, Sam knows me well, don't ya buddy?" He turned to Sam. "I thought you would be the first one to recognize me. After all, I was in your head for a long time." He winked at Dean. "He even crashed at my crib once or twice."

"Lucifer?! How did you escape? What have you done with Cas?" Dean demanded.

"Finally! Deanie's finally catching on! Cassie gave me a little ride out of the cage." Lucifer chuckled. "The spell doesn't work if I'm already in a meat suit!"

"Cas would never say yes to you!"

"Oh really? Like Sam would never say yes? Like Cas would never deceive you?" Lucifer cackled. "Face it, Dean, your friends aren't exactly the most trustworthy!"

"You can't summon the Darkness here," Sam said, a slight tremor in his voice. "You have no idea what you're up against."

"I know exactly what I'm up against, Sammy boy. I fought her before, remember?"

"And it took other archangels, and, you know, GOD!"

Lucifer's eyes suddenly grew cold and hard. "Watch your tone with me, Sammy. I could kill you with a snap of my fingers. I was fighting the Darkness before man was even a thought in my father's head." He got within inches of Sam's face. "You really don't want to test me today, sunshine."

The look in Lucifer's eyes makes Dean fear for Sam's life. He took his little brother by the arm and pulled him away from the devil, and stepped in between the two of them. "You're gonna have to go through me to get to him."

Lucifer let out an annoyed sigh. "I don't have time for this." With a swipe of his hand, the Winchesters flew across the room and hit the walls of the warehouse. A sharp pain shot through Dean's back, and the air is knocked out of him. Dean risked a glance at Sam. Sam was lying unconscious on the ground, blood trickling from the cut on the back of his head. Hold on, Sammy, Dean thought.

Lucifer stretched out his arm. Blood dripped from his palm onto the spell at his feet. "No," Dean said, his voice barely above a whisper. But it was too late.

The first thing Dean felt was the ground trembling. Just a little at first, like a vibration, but then it turned into a full-size earthquake. He heard a loud crack, the sound of solid cement splitting apart. The roof started to cave in, revealing the sky above. It was the middle of the day, but a darkness was surrounding the warehouse, making everything pitch black. It might have as well been night.

Dean had to roll out of the way to avoid a falling cement piece the size of his head. He looked over at his brother. Sam's head moved slightly, then started to shake back and forth, like he was trying to wake up from a bad dream. The wall behind him was cracking, ready to fall over. "Sammy, look out!" Dean yelled.

His eyes opened but the wall was already falling. He shielded his face and rolled over. There was a loud crashing sound and a cry of pain. "Sam?!" Dean cried out, panic in his voice. The a million thoughts run through Dean's head in a second, none of them good. No. Sammy can't be dead. He's okay. He has to be.

The dust settled and Dean saw Sam, still breathing. He let out a sigh of relief and ran over to him. The first thing he notice was the pained look on his little brother's face.

"Dean i-it's my leg," he panted. His leg was caught under a piece of the wall. The grimace on his face said that he was in excruciating pain.

"You're going to be fine, you hear me? Sammy? Look at me," Dean said, cupping Sam's face in his hands. Sam's expression was dazed, and his gaze looked distant, almost day-dreamy. Around them it was beginning to look like a hurricane. The wind was swirling around like a tornado, with Lucifer in the center of it all.

"Sam, we got to get out of here,"Dean said, grabbing his brother by the shirt and hoisting him up, his leg sliding out from under the wall. Sam's arm wrapped around Dean's shoulder, he supported his little brother as he stood. They made way for the door, but it was too late. The Darkness is descending on the warehouse, blocking out any light that was in the place. Dean couldn't see anything. The only reason he even knew Sam was still there was because of the arm around his shoulder.

Lucifer's voice called out, "Hello, auntie! Miss me?"

Then lightning striked in the Darkness, a full-on blinding light. Thunder boomed and the world started shaking. The little tremors turned into a huge earthquake, and Dean heard crashing all around them. There were screams of pain and laughter. Everything was falling apart at the seams, and going into a whole new world of crazy.

The fight could've lasted a minute or an hour or a year, Dean couldn't tell. But suddenly there's a big flash of light and the world stopped shaking. Everything just froze, and the Darkness disappeared. When everything cleared, there lay Amara on the ground, dead.

"See? Told you I could do it," Lucifer said with a sickening grin. Then he grimaced in pain. "The bitch hits hard, though. She's been watching too much WWE."

He rubbed his hands together. "Now are you boys ready for the main event? Apocalypse, part 2. Starring the lovely Lucifer as ruler of the world." His demeanor changed from easygoing to dark in a millisecond.

"But I'm afraid you boys won't be a part of this story." Then he smirked.

"So that's the plan? Kill us?" Sam said, defiance in his voice. Sam really didn't know where this sudden courage was coming from, but at least it made him feel brave, even for a millisecond.

"Well, duh," Lucifer said. But then he frowned. "But maybe I won't kill you all at once. At least not you, Dean,"he says, with a glance at the hunter. Then he turned to Sam, a sick, mischevious, twisted grin on his face. "But you, Sammy? I know exactly what to do with you."

One second Sam's hand was around Dean's shoulders, the next he felt the comfort of his little brother's presence disappear, along with Lucifer.

"Sammy?" Dean called out. Oh no. No no no no. "Sam?!"

A million worrying thoughts ran through Dean's head. He can't be gone. He can't be dead. Lucifer couldn't kill his own vessel, could he? He wouldn't kill my baby brother, would he? The answer gnawed inside of Dean, ripping him apart, piece by piece-yes, yes he would.

Dean felt a lump in his throat as he looked around the empty warehouse. I'm sorry, Sammy. I'm so, so sorry.

"SAMMY?!"