Sam poked his head into the room where they had stashed Aviella. She looked up from the book she had been reading.

"You've decided not to kill me." She said with a smile.

"Uh, yeah." He said, making a move to break the circle of the Devils trap that bound Aviella.

Or at least the trap that theoretically should have bound her, Aviella got up and walked out. Looking at Sam with an amused expression.

"I'm not a demon." She said simply. Sam blinked.

"It was just a precaution." He said eventually, the girl just smiled.

"I cannot blame you." She said sadly, they began to walk back to where Dean and Cas were.

"So what's your deal?" Sam asked, unable to stop himself.

"My deal?" She asked, confused.

"Why do you want to help us."

Aviella pondered the question. "Why are you a hunter Sam? You did not want the life you live. You want a family. You want to be normal. But as hard as you try you know that will never happen. Because that is not who you are, its who you want to be. You still have demon blood in you. And you are desperate to prove that it's not who you are. But at the same time, you're desperate to not be like your father."

"So you can read minds?"

"No," Aviella said with a shake of her head, "just faces. I've been around while, I can read people. You forget I'm immortal. I don't possess people and I don't have vessels. I'm 16 forever, in 300 years when they are telling legends of Sam and Dean Winchester I am going to look like this."

"You never answered my question." Sam said simply.

"Because you need my help."

OoO

"There is going to be a war." Cas warned.

"How do you know that?" Dean asked

"It's logical." Aviella interjected before Cas could say anything. "Angels guard the souls in heaven. What happens when there are no guards?"

"An army of Hell will rise and attempt to steal those in Gods domain." Cas said.

"Oh," Dean muttered, "That doesn't sound good at all. How do we stop it?"

"Reopen the gates of heaven." Sam suggested.

"Close the gates of hell." Cas suggested.

"Not an option." Dean interjected

"Dean," Sam said. "We have a chance to close the gates of hell, forever. Stop hell from taking over innocent people's souls."

"Its not worth your life Sammy."

"It may not have to be." Aviella said. Cas, Dean and Sam looked at her sharply.

"Is their another way?" Sam asked. Aviella's eyebrows furrowed.

"I was thinking. Demons, they need to crawl their way out of hell. But they don't just ooze onto earth through cracks on the ground. Hell must have pathways to earth. What if we don't close the doors of Hell? What of we just get rid of any roads there?"

"We've been through some of those portals." Sam began, "We can maybe close them off.".

"But maybe you haven't been through all of them." Aviella said, "We need to find all of them and lock them down."

"But what of the demons that are still on earth?" Cas asked, "If we block the way out, we also block the way in. Demons will be stuck here. Forever."

"What if we got rid of all the demons on earth? Exorcised them out." Sam asked. "Everyone of them. Then quickly blocked the way to hell. Would that work?" Everyone looked at Cas for answers. He stood there thinking.

"It may work. I can make no guarantees, but if Dean refuses to allow Sam to sacrifice himself then it seems to be our only option."