Supernatural Little Sister

Lost

Allison: 22
Dean: 31
Sam: 28

This is a request from @sune172002 :)

"This seems like as good of place as any." Sam says as the brothers enter a bar. The brothers instinctively sit down at a table for 3, even though it's just them. "I still can't believe that Mrs. Douglas knew about the ghost. If she told us, the job could've gone much faster." Sam shakes his head and looks to Dean but he's not even listening. "Dean, what's wrong?"
"What's wrong? You know what's wrong." Dean spits.
"We have a few leads, Cas is searching, Bobby is reaching out to the hunter community...it's not hopeless, Dean."
"How does she just disappear like that, Sam? Without a trace?" Dean asks, staring off into the distance.
"It's only been a month. Maybe she..." Sam trails off.
"Maybe she what, Sam?" Dean yells, now locking eyes with him.
"I don't know, Dean! I'm trying to remain calm and maybe come up with some logical answers..." Sam says.
"A logical answer for how our 22 year old sister, who happens to be a damn good hunter, disappeared from her bed without a peep nearly a month ago? Good luck with that." Dean sighs and then asks the waitress for two scotches, neat. "Please stop trying to act normal, Sam. I'll work, but I won't be happy until I know where she is." Sam glares at his brother and Dean starts to sip his drink. Dean looks around the bar and notices how barren it is inside. "Pretty empty for 6 o'clock." Dean notes but nearly spits out his drink when he sees Allison sitting at the bar next to a guy.
"Am I hallucinating?" Dean mutters and Sam looks.
"Oh, my God, it's Ally." Sam says.
"She's been fine this whole time? Hunting by herself, flirting with guys?" Dean says, his anger escalating.
"Dean, we don't know that...but it really does look that way." Sam says as Dean gets up and storms over. Sam follows his brother over to the bar.
"What the hell is going on, Ally? We've been worrying our asses off!" Dean yells, grabbing her arm.
"Excuse me?" Allison asks.
"Do you know these guys?" The man next to her says.
"No." Allison shakes her head. Sam's brow furrows with concern but Dean is still furious.
"Ha ha, Ally. Seriously, where the hell have you been?" Dean yells. "Everyone is worried sick. Bobby, Jody, Cas...us. Did you even think about anyone else but yourself?"
"I don't know what you're talking about...how do you know Bobby? Why is he worried?" Allison says, scared.
"Ally—" Dean starts.
"Dean, she has no clue who we are." Sam says, holding his brother back. Allison's big, green eyes are full of confusion and worry.
"Um, I'll see ya later, honey." The guy says and walks away with his drink.
"What's going on?" Allison asks, her voice trembling. "Who are you people?" She asks as she gets off the bar stool.
"Oh, Ally. What happened to you?" Dean hugs her but she doesn't reciprocate the embrace.
"Dean, easy." Sam pulls his brother back. "We're your brothers, Sam and Dean Winchester." Sam says calmly.
"I don't have any brothers." Allison shrugs off the information nervously.
"Let's take her back to the bunker." Dean says.
"Bunker? What the hell is happening? I'm not going anywhere with you creeps!" Allison yells.
"Ally, please." Dean begs. Allison turns to leave but Sam stops her gently with his hand.
"Can you tell me anything about yourself?" Sam asks. Allison turns to him and sighs.
"My name is Allison Winchester and I'm from Lawrence, Kansas. My parents names were John and Mary, but they're both deceased. I've lived with my Uncle Bobby in Sioux Falls, South Dakota for the past 7 years and I'm an only child." Allison says. Dean's heart breaks as he realizes his little sister has no clue who they are.
"A-and you love rock and roll and burgers and big dogs and you are super ticklish—" Dean rambles.
"Dean—" Sam stops him as Allison looks at the man, frightened.
"Ally, baby..." Dean starts, tears falling down his face. Sam bites his lip anxiously as tears brim in his own eyes.
"What's going on?" Allison asks.
"We're your family." Dean chokes out. "Look at this. You drew it for me when you were five and gave it to me for Christmas." Dean pulls out an old piece of paper with a poorly drawn family portrait on it from his wallet. Allison looks sadly at the helpless man in front of her.
"I'm sorry, I don't know what this is." She says. Sam pulls a picture out of his wallet and hands it to her.
"When I left for Stanford, I missed you like crazy. I kept this picture of you and Dean in my wallet and looked at it at least once a day." Dean looks to Sam.
"I didn't know that..." Dean says as he peers at the picture over Allison's shoulder. The picture shows Allison drinking a milkshake with Dean's arm around her, laughing, as Allison makes a funny face. "I remember this! You were 13 and the milkshake was too thick at—LuLu's Diner—I told you you could only get it to come through the straw if you made a stupid face. Then Sam took this picture." Dean smiles and Allison shakes her head.
"I don't know what's going on. I don't know how you know my name or my Uncle Bobby or how you have this picture but I don't know who you people are. I want to believe you, I really do, but I have to go home." Allison says.
"So, you said you live with your Uncle Bobby in Sioux Falls?" Sam asks as Allison starts to leave again.
"Yes." Allison says.
"Well, Sioux Falls is about 200 miles from here and 2 weeks ago Bobby Singer sent out a search party for you." Sam says showing her an email Bobby sent out to all the hunters he knew.
"Why would you go to a bar 200 miles from home?" Dean asks.
"I—I don't—" she starts.
"Isn't that a little strange?" Sam asks and she nods. "If you come with us, we can help you." Sam says. Allison nods and Sam takes her out to the car. Dean pulls out his phone, dials quickly and runs his fingers through his hair.
"Cas, we found her, but she needs your help."