A/N This starts around the beginning of series 3. It'll probably have it's own story arcs, but mostly go along with the shows. There will also be eventual Destiel.
CHAPTER ONE.
It all started with a phone call from Bobby.
"Bobby, we're in the middle of a case!" Dean argued, stranding back to back with Sam in a haunted house they had seen too many times on the current hunt, his phone in one hand, a gun with bullets full of rock salt in the other and a clear idea of where the body was buried in the garden out back.
"This isn't a case Dean, this is different" Bobby shot back. "I'm on my up to you" He told him, hanging up just as Dean saw the ghost – he aimed his gun and shot, before both brothers ran through the house and kicked in the back door, and ran into the garden.
On the way back to the Motel, the brothers got into another fight over the fact Dean still only had ten months to live and they were doing nothing to try and break the deal. As usual, Dean insisted that he couldn't be saved before refusing to say anything else, turning up the radio and looking straight ahead – refusing eye contact with Sam, making sure he had the last word.
Bobby was already waiting for them when they reached their room, sat on the edge of the bed Dean had claimed – behind him laid a teenage girl, no older than 20. "So what's so important apart from a case that you had to drive all way up here?" Dean asked – ignoring the obvious clue, Bobby motioned to the sleeping girl.
"Scarlett Winchester, that's what…or who" He told them. "She's your sister, eighteen years old, been trying to track you down for the last five months"
Both brothers stood there in silence. "…We don't have a sister" Sam pointed out; he turned to Dean for conformation on the fact, but his older brother just stood staring at the girl. Eventually, he snapped out of it and shook his head in agreement.
"We definitely do not have a sister, I think Dad would of told us if we did" Dean said, both Sam and Bobby looked at him with raised eyebrows, causing the older brother to roll his eyes.
"Dean, I've had her in a devils trap, dunked her in holy water, cut her with silver, chanted how many exorcisms – she's definitely human, and she definitely knows who you are" Bobby listen. Both brothers considered it for a moment.
"Maybe she's just some creepy stalker" Dean suggested with a small shrug.
"If she was your stalker, she probably wouldn't have been trying to track you down for five months" Bobby replied, his arms crossed. Suddenly, they heard a soft groan and looked over to the bed. Scarlett rubbed her eyes, before lifting herself up on her elbows and spotting Sam and Dean, then sitting up fully.
Both brothers tried to avoid what they obviously both were thinking. Apart from the brown hair that was hardly secured in the side plait she styled over her right shoulder – the striking appearance to their Mother. She blinked a few times before fixing her stare on them.
"Nope, she's not ours" Dean claimed, Scarlett rolled her eyes, mumbling something like 'knew it' under her breath.
"I don't know, Dean" Sam said, studying her. Dean spun round and looked at Sam as if he was a complete idiot. "Where are you from?"
"San Diego, of course I spend five months looking for you and then you end up a five hour drive from where I lived" Scarlett complained. Sam tilted his head back a little, thinking – Dean carried on staring at him.
"About, nineteen years ago. Dad went on one of his longer hunts to San Diego, didn't come back for about 3 weeks. Helping a woman out with a ghost" Funnily, Dean wouldn't have remembered unless it hadn't of been one of the times he left them alone over Christmas.
"When's your birthday?" Dean asked.
"27th of September" Scarlett answered, wondering why her birth date mattered when they or at least, just Dean wouldn't accept the fact they were related. "I have my official birth certificate" She added.
"Does it have our name on it?" Dean replied, sounding unnecessarily harsh – annoyed that this was adding up.
"I only found out you existed a little under a year ago, I know your Dad did though" She revealed, crossing her arms defensively.
"Did Dad…visit you?" Sam asked, Scarlett shook her head – her expression suddenly changing, her eyes seemed to go darker; full of anger and sadness.
"No, he drove my Mum crazy…literally. Left before she could tell him she was pregnant, un-traceable" Scarlett said, her voice sounding almost sarcastic. She decided to turn her attention to the hem of her oversized jumper, fiddling with it.
"Yeah, well, he had to sons to look after" Dean replied in a snarky tone, Sam shot him a warning glance and Scarlett looked up.
"I see that now" She said, narrowing her eyes. Bobby rolled his eyes at their bickering. Dean went silent, Sam stood in front of Scarlett – trying to figure her out. "Listen. I know it's kind of unbelievable – but do you really think I'd let Bobby cut my arm open with an iron knife if I was a demon?" She asked, rolling up her sleeve and revealing a bandage which covered the majority of her lower arm and was stained red. "Hurt like a bitch" She mumbled, covering it back up with the sleeve and wincing at the pain.
"Listen boys, I got in touch with Ellen – she told me that your Dad came visiting after a hunt in San Diego, got a bit too drunk and started rambling on about some woman he met who looked just like your Mother" Bobby told them, Dean pulled a chair from the table and sat down on it – staring at Scarlett before sighing and putting his head in his hands.
Scarlett gave her brothers a pleading look, and then perked up a little. "If it helps, I might have a hunt for you" She mentioned. Dean looked up, his face telling her to go on.
"Where I used to work, there's been a series of mysterious disappearances" She started, but stopped at the look Sam and Dean gave her – she rolled her eyes yet again, knowing what they were thinking. "I know how you guys work okay? That isn't the full story. These girls have been leaving the building, every Thursday for the last three weeks, at exactly 10:07pm – my boss, he swore he saw black eyes on each of them as they walked out after checking the security tapes; plus, traces of sulphur" She explained, finishing with a slight smirk. Both brothers looked at each other and raised their eyes.
Sam considered it, Dean still couldn't get over that he had a sister – if she was telling the truth that was. She wasn't a demon, or anything else they had hunted – she was human. But, even if she was human…it didn't mean she was telling the truth.
But the resemblance to their Mum, to him, to Sam – it was almost terrifying. The only thing that looked out of place was her bright blue eyes, instead of either brown or green. "It's a five hour drive, like I said" Scarlett said.
"It's worth checking out, I guess" Sam replied with a shrug, still sounding unsure. He turned to Dean, who he was expecting to kick up a big fuss and try to kick Scarlett out and do their best to never see her again – but Dean just looked from his brother, to Scarlett.
"If we go now we can get there for sun rise" He said, jumping up and pulling his jacket from over the back of the chair. "Bobby, you joining us?" He asked, the smile he was wearing an obvious fake.
"No, I've got some business to do" Bobby told them, picking up the keys to his car and giving Scarlett a reassuring pat on the shoulder before walking over to Dean. "Give her a chance" he whispered to the eldest brother.