Sam Winchester swallowed hard and glanced at his older brother as he put his hand on the door handle. Dean mouthed 'One... two... three!' on three, Sam opened the door and the two of them piled in baring shotguns. The circled out checking each inch of the dusty old room.

There were no windows, and only one door in. The floor what covered in twenty years worth of dust and dead rats. A single light bulb hung in the middle of the room, its light faded and yellow. The only furniture in the room was a desk and a chair which was currently lying on its side.

Dean frowned, lowering his shotgun and catching Sam's eye.

"It's there supposed to be, I dunno... a reaction of some kind? Like, flickering lights or maybe the goddamn ghost?"

"The pattern isn't always the same, Dean." Sam kept looking, the hair on his arms started to stand on end.

"Yeah it does. That's why it's called a pattern."

"Dean get ready..."

He lifted his weapon again, his eyes searching the room.

Suddenly the door slammed shut, Dean couldn't help smirking.

"You can say it if you want." Sam rolled his eyes.

"Say what?"

"Some reference, I can see it brewing in that head of yours."

Dean lowered his gun, pouting slightly. "Well thanks, Judas. Ruin the party why don't you?"

Sam snorted, and then looked over. A young girl with blood soaking through her clothes and dark rings under her eyes was standing right behind his brother.

"DEAN!"

But the warning came too late. Dean turned just in time to be thrown back against the opposite wall, his shot gun went flying. Sam swore and aimed at the ghost, firing but the girl flickered and was suddenly closer to him. He stepped back, firing again but she dodged it in the same way.

"SHOT HER SAM!"

"What do you think I'm doing?!" Sam retorted, quickly reloading. By the time he lifted his shot gun again, the girl was on top of him.

She screamed loudly, the sound was deafening. Sam winced and could only cover his ears as the sound filled his head. He felt like it was clawing into his mind and trying to rip his apart from the inside out. He fell onto one knee, pretty sure his ears were bleeding.

Dean was still pinned to the wall, he gritted his teeth and squeezed his eyes shut, willing the noise to stop.

The door suddenly burst open and a figure stepped into the room. They cocked the shot gun in their hands and fired, hitting the wailing spirit in the chest. The poor soul dissolved quickly, the noise stopped leaving only a fading echo.

Dean slumped to the floor, the invisible hand holding him to the wall vanishing. Both the Winchesters huffed, as the pain eased. They looked up to see who their saviour was.

It was a girl of no more than twenty one; her light brown hair was cut short into a straight bob. She had a half fringe and on the opposite side of her head a portion of her hair was shaved off. She wore tatty black jeans, a striped blue t-shirt and an open denim shirt. She'd put the gun down on the desk and was currently looking through the draws.

Dean glanced at Sam and then spoke.

"Uh... thanks. But if you don't mind me asking, who the hell are you?"

"Oh, haha, very funny." She carried on searching until she came to a locked draw. She bobbed down and took a lock picking set out of her jeans pocket and started picking the lock.

Sam spoke next. "Sorry, do we know you?"

She picked the lock and opened it. Inside was a necklace with a lock of hair inside the pendant. She took a shell out of her shot gun and emptied the salt onto the hair. She then lit a match and dropped it into the draw. She turned rubbing her hands together.

"You are welcome, you amateurs." Her face was pretty with high cheek bones and a defined jaw. Her eyes were a mix green and hazel, her lips small but full. "What are you even doing here? I've told you a thousand times, I can take care of myself."

They looked at each other, checking the other was as confused as they were. They both looked back to the girl.

"Look, kid. I honestly have no idea who you are. But you saved our asses so I say I owe you a beer." Dean's eyebrows rose.

The girl frowned deeply, looking at the both of them. She grabbed the light bulb and brought it closer to their faces. They both winced at the suddenly increase in light. The girl's eyes widened and she seemed to go a little pale.

"Holy shit..." she muttered.

Dean frowned. "What? Have I got crap on my face?"

The girl laughed slightly, a look close to amazement on her face. Sam cleared his throat, whispering to Dean. "Why do I feel like a monkey at the zoo?"

Dean nodded. "Yeah, I know the feeling."

"I'm sorry... it's just so weird..." she trailed off, looking away suddenly and frowning in thought.

"What's weird?" Dean took a step forward. There was something about this girl. He wanted to put his arm around her, protect her.

She quickly turned around, throwing a flask of water into his face. He stood there for a moment, then sighed and wiped his face on his sleeve.

"Do you mind not- HEY!" he yelped in pain as she stabbed him with a long silver needle. "Jesus that hurt!" he held his shoulder, frowning angrily. He took back his previous thought, now he wanted to kick her ass.

Sam had started to laugh when she threw holy water in his face. He spat, rubbing his eyes. She stabbed him in the forearm and he shouted in pain.

"Dude, not cool!"

She stared at them again, her amazement now confusion.

"Satisfied?" Dean asked bitterly, rolling his shoulder back and forwards.

"I can't believe it's you! I mean you look so young, how could...?" she trailed off as if a thought just occurred to her. "Oh no... no, no, no. Sam what year is it?"

"2009?"

The girl's eyebrows shot up. "Cas, you son of a bitch..." she muttered to herself.

"What did you say?" Dean asked, stepping closer.

"Look, why don't I just make this easier for you guys. Basically, a couple of angels got into a fight and I got in the middle of it and now I've been shot back into the past." She paused. "I'm guessing. Otherwise I'm dead and my heaven is messed up."

"Well, you're not dead." Dean frowned.

"Well that's a relief. I was hoping heaven would have more steak." She half smiled a single dimple showing on her left cheek.

"You and me both, sister." Dean smiled suddenly, all his anger towards her pouring out of him.

But Sam still wasn't happy. "So, who are you?"

She looked at him, pausing for a moment as if deciding whether she should tell them or not. She exhaled slowly, and then told them. "My name is Cassidy Winchester." She looked at Dean. "And I'm your daughter."

A cold panic ran down Dean's spine and he swallowed hard. "What?"