a/n: Sorry for the long wait! I'm planning to finish this fic by this Thursday; before my exams starts. Enjoy and please review!

A lot of shit can go down in a month, especially if the Winchesters are involved!

The Power of Two: Three Weeks Later

Dean can remembered it like it happened yesterday, how could he not? Being transported into the future wasn't something that you just forgot. The Croatian Virus, Chuck with his golden toilet paper, Cas as a hippie and himself as a hard ass. But none of those meant anything now, they never happened. There was one thing though, that would stick with him no matter how much he wished that he had never known, that his future-self had never shown him.

Sam as Lucifer.

It was his worst nightmare, not just figuratively but quite literally. He had nightmares about it every time he went to bed; it was there when he closed his eyes. It was the 'what if's'; what if Sam said YES, what if Lucifer found away to take Sam as a Vessel without his consent. But what made Dean even more sick to himself, was the fact that he didn't have much trouble picturing Sam as the Devil.

He knew that it was wrong, but considering all that had happened it wasn't as if it was unexpected. Sam had time and again given into that darkness inside of him, Dean just hoped that because Castiel had purged the Demon blood from Sam's system—via Angel-mojo—that it would be different this time.

Dean did hope that that was the case; it had been so far, after all.

The whole mass-grave that Lucifer had been digging, the incantation that he did, brought the four horsemen to Earth. War, Famine, Pestilence and Death. They had defeated and killed each to get their rings, all but Death because you can't kill Death (dummy). It was the only thing that they could do to help track down Lucifer and hopefully find Nathan again.

And Nathan... Nathan was a whole other story. Bobby had been out of it since Lucifer got Nathan, even Dean and Cas were effected by it—Sam was the one who didn't seem outwardly effected by Nathan's absence.

And it was true; Sam wasn't as effected as the others. He was glad of Nathan's existence; sure, now that there was another Winchester, there was someone else that Dean could baby. He knew that it was selfish of him, but he was sick of being treating like a child—even if it may have been deserving. But now that Nathan was gone, Dean was back in 'Sammy' mode. He hated it more than anything and sometimes he found himself wondering what life would be like if his and Dean's roles were reversed; if he was the older brother and Dean was the 'baby' of the Winchester clan. He hated being treated like the kid and he knew that it was old news, but it always stuck. It did seem like he and Nathan did have that in common—but was it fair that Dean had let up Nathan but not him as much?

Sam knew what he was going to do, what he needed to do. He told Dean the plan, and of course he had object and gave the 'there's always another way' speech, but Sam really didn't see one. It wasn't long after though, that Dean realized the same thing, as much as he hated—despised—this plan and the situation that they were stuck in.

Dean told himself that there was no other way, that this was there only option—"at the moment!" He wanted to scream at Sam. This was his nightmare coming to life, Sam saying YES to Lucifer. Just because he thought that he could control the fricken Devil because Bobby did it with a low-class Demon. And the Demon blood was just too much. What was the point of Nathan getting Castiel to rid Sam of the Demon blood, when he was just going to guzzle down three two-liter jugs of Demon blood anyway? It was the worst thing that could have happened and what Sam could do.

Bobby was too out of it to assist, and Cas had somewhere along the line depleted most of his Angel-mojo—and Dean wasn't quite sure how something like this was possible. But apparently it had happened, and there was no time to fix it now anyway.

"I still don't like this." Dean grumble, his face scrunched up as he watched Sam.

"I heard you the first time, Dean." Sam growled back, jerking one of the jugs of Demon blood out of the Impala's trunk.

"Apparently you don't think the same." Dean told him.

"You think I want this?" Sam demanded, the lips of the jug at him chin. "This is a lot of blood, Demon blood, that I have to drink in order to do this. I don't like what it does to me, Dean, the things that it makes me do. But it's the only option that we have, to take out the Devil and send him back to his cage, and get our brother back."

"And what if you can't? Hmm?" Dean shot back.

Sam lowered the jug and looked at Dean, his jaw clenched. "Well, I'm gonna have to or you're gonna have to find another way to kill me and get Nathan back, now aren't you?" he retorted and before Dean could yell back at him or he could stop himself, he lifted the jug to his lips and started drink the Demon blood.

Sam didn't want to say that he liked it, but he didn't not like it either. Demon blood was like a drug, his drug, his crack. It was his addiction as much as it disgusted him to even think about it. It made him feel powerful and strong, and made him feel as if he could do anything, it made him able to do anything. He was above everyone and anyone.

Sam shook his head, taking the jug from his lips, breathing a little heavily. He was nearly done this container, but he didn't feel full in the least—more like he felt hungry. He wanted more and he found himself lifting the container to his lips eagerly—a little too much so for Dean's liking; this was his least favorite part about this plan.

The plan was for Sam to drink the Demon to make him stronger, make it so that he might at least have a slight chance of controlling Lucifer when he said YES. But by the end of it, after three two-liter jugs of blood, he wasn't like the same. He got that look in his eyes, the 'hooked on Demon blood' look, the one where he thought that he was better than everyone else.

"Sam!" Dean snapped.

Sam looked at him with raised brows as he wiped his mouth on the cuff of his jacket.

"Remember what we're here for?" Dean raised his brows.

"Of course, Dean!" Sam gave him his paten bitch-face. "Just because I drank 6 liters of blood, doesn't mean I'm too doped-out to remember the whole point of drinking it in the first place!"

"Good. Now remind me of the plan." He said, just to make sure.

Sam rolled his eyes. "We're going into the house to find Lucifer, when we do; I'm going to say YES. After he takes me as a Vessel, you're going to open the temporary portal to the Pen and I'm going to take control and through myself and Lucifer into it." he recited. "Hopefully Lucifer brought Nathan with him, otherwise we're screwed in that point."

"Good." Dean gave a firm nod. "No hesitation."

"No hesitation." Sam repeated.

The thing with plans was the fact that they never turned out quite the way that you wished them to, especially when the situation needed to go a specific direction and way—but when you got around to it, things went awry.

They made it up to the third floor without seeing a Demon, and even then they couldn't find any. Neither brother commented on the fact, each knowing now that Lucifer knew that they were coming... but despite that, didn't put up any guard. But there was no way that he'd know what their plan was, that they didn't really intend to kill him.

They walked into the third floor apartment, and standing there, next to the row of windows, was Lucifer himself.

"Dean." he greeted cheerfully as he smiled, turning from the window, his shadowed body outlined from the moonlight. "Sam! I'm glad that you guys could make it, I was afraid that I was going to have to send someone for you."

"We found our way just fine, thanks." Dean voiced sarcastically.

"Dean Winchester," Lucifer sighed. "I was hoping for just a one-on-one with your brother, but I am glad that the whole family could be present for what soon happen."

At the moment, neither brother realized Lucifer's use of the 'whole' family.

"And what's about to go down?" Dean asked.

"Sam saying YES, of course."

"Why do you think that I'm going to say YES?" Sam asked stiffly, feeling the Demon blood course through his veins, making he want to do something dangerous and reckless like take on the Devil physically.

"This is Detroit, Sam. Exactly the date and time where I said that you'd say YES." Lucifer said reminded him.

The brothers glanced at each other tight lipped for a moment.

Sam turned to Lucifer. "I will say YES," he agreed begrudgingly. "On a few conditions."

"I am a very reasonable man, Sam." Lucifer nodded. "I was telling the truth when I said that it was not my intention to hurt you."

Sam glared at him, his nostrils flaring as he sucked in a deep breath. "You don't touch Dean, Bobby or Castiel." Sam told him. "You give Nathan back, unharmed, and you leave him alone as well. You break any and this is off."

Lucifer looked at him for a moment before he turned and leaned against the window frame, his arms crossed over his chest. "You know," he said conversationally. "People always think that the Devil runs with fire." he breathed a breath against the pane of glass; a fog cloud spread on the smooth surface, but didn't stop there. It spread, until it covered the whole of the window, the moisture crystallizing as it seemed to freeze. "But what they don't realize, is that I run cold." the corner of his lips curved upward as he ran his finger along the surface of the frosted window, his warm fingers clearing the way. He turned back to them, the clear picture of a pitchfork on the window. "Despite that, you can trust me, Sam."

"Right." Sam scoffed, glancing at Dean. "We wanna see Nathan first."

"Your wish is my command, but if you go back on our deal and don't say YES, I can make you're an only child with the snap of my fingers." Lucifer threatened, and it wasn't empty either, the Winchester brothers could see the real Devil for once, not the 'pleasant' facade that he usually cast.

They swallowed inaudibly and Lucifer sent them a disarming smile.

"Boyd?" Lucifer inquired, continuing to stare at the brothers.

Dean and Sam looked at each other with furrowed brows, but gave jerks when a Demon seemed to appear of the shadows in the corner of the room. In front of him, a hand on his shoulder was Nathan.

"The whole Winchester clan." Lucifer repeated.