A/N: Thoughts are in italics.
"What's going on? What happened?" Dean asked, stomping into the library.
He looked around the room and saw a teenage girl sitting next to Sam with a mug in her hands. She had sea-blue eyes and long, blond hair in a plait. Confusion filled Dean's mind. Sam just sat there, waiting for Dean to say something.
"Who are you?" he pointed at the girl, but she was just as confused as he was and did not respond.
"Lilith. Or at least, Lilith before she became a demon," Sam answered and Dean's eyes widened. Even though she was still human, he still wanted to kill her for starting the apocalypse and making Sam suffer so much.
"Why is she here?"
"She just turned up at the door and claimed she had a vision that told her to come here for help. Then Gabriel heard the angels on the angel radio talking about her coming to this timeline from the past. They plan on killing her so that she never ends up opening Lucifer's cage."
"So… what's wrong with the angels killing her?" Dean was confused again. If they kill her, Sam would never have had to go to Hell and so many people would still be alive. He saw nothing wrong with that.
"She's an innocent girl, Dean. We can't just send her to her death."
"What does Cas and Gabe think about this?" he was still unsure about keeping her here. What if she's just pretending? What if she knows everything she did and wants to kill us?
"I don't know." Sam shrugged and looked at Lilith.
"Alright then." Dean closed his eyes and began to pray. "Dear Castiel, who is probably running around in heaven, come here right this instance! Oh, and err, bring your brother. The extremely annoying one."
He slowly opened his eyes when he heard the sound of fluttering wings and saw Gabriel and Castiel appear in front of them.
"How the hell did you do that?! And... what are you?" Lilith's eyes widened and she nearly dropped the mug.
"Deano, Castiel told me what you said. I'm not that annoying," Gabriel scoffed then turned to face the girl. "What do you mean what are we? We look human. Don't we?"
Sam, Dean and Benny nodded but Lilith shook her head with a terrified expression on her face.
"You don't look human! You're massive and glow-yy. Very bright. You – the one in the trench coat, you're bright blue. And you – the short one, you're shiny gold."
Lilith pointed at the two angels.
"Hey. I'm not too short. My true form is two times the size of this bunker, much taller than Moose and Squirrel here. I never understood that. Crowley was the weird one." Gabriel pointed at the teenager angrily.
Sam rolled his eyes then asked, "So what do we do?"
"First, we find out how Lilith can see Cas and Gabriel's true form."
They sat there in silence, trying to think of how Lilith could see their true forms.
"I have an idea!" Gabriel stood so quickly that he knocked over the chair.
"Wow. Really? I didn't think that you would actually take this seriously," Dean replied.
"No one other than angels should be able to see our true forms. This could be very dangerous."
"Ok, so what's your idea?"
"Me and Cas take her to Heaven and see if the angels can find out what or who she is."
Sam and Dean's eyes widened at this idea. They crossed their arms and glared at Gabriel.
"The angels are trying to kill her. You can't take her to Heaven." Sam shook his head disapprovingly.
"What else could we do?"
"We hit the books. Read until we find something."
"Wait… someone's praying to me. I gotta go. Bye! Have fun!" Gabriel waved and was about to vanish but Sam shouted at him before he could leave.
"Gabriel! I know you're lying. You're just trying to get away from doing research."
"Nerd," Dean and Gabriel huffed at the same time.
"Lilith?" Sam knocked on the door of the room that they had let her stay in.
"Come in."
"Hey. We need to talk to you," Sam said politely.
"Ok. Could I get some coffee first?"
"Yeah, sure. You go to the library, I'll go get you your coffee."
Sam walked into the kitchen and poured coffee into a mug. When he arrived at the library, everyone was sitting around one of the large tables, with piles of books next to them. Sam placed the mug next to Lilith, then sat down opposite her.
"Ok. First things first, do you know how you got to this timeline?"
"No. I was in my house, sleeping in my room. When I woke up, I was in the same bed, but it was all dirty and the house was abandoned. I have no idea what happened. I swear."
"It's ok, we believe you. Were you with any of your family at the time?"
"Yeah, I was with my sister, Lydia."
"Wait," Dean remarked. "Does she have brown-ginger hair?"
"Yeah. Why?" Lilith replied, confused.
"Is this her?" He pulled out a picture of a brown-haired woman and showed it to Lilith.
"She looks a lot older than when I last saw her, but yeah, that's definitely her. Where did you get that?"
Dean turned to Sam and chuckled, "Well Sammy, white-eyed demon Lilith here, is my daughter's aunt."