Disclaimer; I don't own any of the characters.

Warning; AU, Character deaths. Angst angst and more angst.

x

Dean Winchester believes in ghosts.

His parents told him he was being silly when he announced his belief as a child, and his brother stood behind them and laughed. He tried again a couple of years later, as a teenager, and they asked if he'd been watching late-night scary films again. Sam smiled a secret smile and poked his tongue out at Dean, flashing him a wink and some dimples.

After the third try, Dean gave up.

His faith in the existence of the Supernatural didn't come from an over-active imagination. It wasn't the result of horror films or sci-fi TV shows or old ghost stories.

It came from his brother; Sam Winchester. Sam was four years younger than Dean, but already taller than him. He kept his hair long and shaggy, falling into hazel eyes and brushing broad shoulders. He was always wearing ridiculous check shirts and jeans, with tatty old converses on his out-sized feet.

Sam Winchester died in a fire when Dean was four years old.

It was one of those freak fires that no one can really explain; his mother said his father had left the oven on, and his father remained certain that his mother had left something in the microwave.

Dean couldn't remember much more than the heat and the smell and the smoke that filled his throat and made him choke. He could remember hearing Sam screaming, and then his mother screaming as the ceiling collapsed in the nursery. He could remember the fireman who crouched down to tell him that his brother hadn't made it out.

Whose fault it was the fire had started had seemed pretty irrelevant after that.

At four, Dean hadn't understood what death meant. He didn't know what his Mom had been trying to say when she said Sam wasn't coming back. That he'd gone to a better place.

She'd been wrong, anyway. Dean had waited for years, but eventually Sam came back to him.

It had been the fourth anniversary of Sam's death - Sam's fourth-and-a-half birthday. Dean had been standing on the patio of their new house, watching as his parents embraced under the tree they'd planted in remembrance of their lost son, when Sam wandered up next to him.

"Why's Mommy crying?" he had asked, looking up at Dean. Dean had shrugged and turned his head to face his brother.

"She missed you," he replied, and Sam's mouth opened into an O.

"I didn't mean to make her worry," Sam had told Dean, and Dean had smiled, taking Sam's hand.

"I know, Sammy," he said softly, squeezing his brother's fingers. "It wasn't your fault."

Dean hadn't said anything when his parent's came back over. Sam slipped away silently, vanishing while Dean's back was turned, before he had a chance to say goodbye.

But later that night, while he was lying in bed, he felt Sam slide in and curl up next to him.

Sam stayed with Dean as he grew up, growing with him. Sam sat on Dean's bed and listened to him rant nervously about his first date, and his first kiss, and the first girl he fucked. When Dean went through his sexuality crisis at sixteen, Sam sat with him patiently and talked him through it. And when Dean brought his first boyfriend home, Sam was standing right next to him as he introduced Cas to their parents.

It never seemed like a big deal that no one else could see Sam. Dean learnt in a matter of weeks that it was a bad idea to talk to Sam in public, so he kept their conversations for when they were alone. Occasionally, when he was still a kid, he'd slip up and the other kids would avoid him for a while, but he was good at blending in and disappearing into the crowd, so he was never an outcast for long.

Sam wasn't always with him. Sometimes he'd vanish, without warning, and wouldn't come back for days. Once, he left for four months, and Dean nearly went mad with worrying that he wouldn't ever return.

He came back when Cas broke up with Dean, and Dean spent a whole night biting back tears because everyone he cared about was leaving him. He came back and curled himself around Dean in the bed that was slightly too small, just like he used to when they were little.

"I'm sorry," he had murmured, stroking a hand across Dean's stomach and burying his nose in Dean's hair. "I'm so, so sorry."

Dean hadn't replied, hadn't known what to say.

He didn't speak to Sam for another week.

As he grew older, Dean retreated further and further into himself. He stopped going out with friends, stopped bringing home girls and boys. His parents worried, and his teachers expressed concern, and the few kids who still cared asked what was wrong, but Dean didn't have an answer for any of them - at least, not one they'd understand. The psychologists and psychiatrists and psychotherapists that his mother and father sent him all blamed his antisocial tendencies on the loss of his brother. Dean just shrugged and looked away, unable to explain that he'd never actually lost his brother. Not in the same way his parents had lost a son.

The truth was nowhere near as traumatic, but much more disturbing. The truth was simply that he didn't need anyone other than the ghost of his brother. Sam was all the friends he needed, all the company, all the confidants.

Sam was everything.

Dean was twenty two when he realised his feelings for Sam had gone past brotherly. He was twenty two, fresh out of college, with a new job and a new home and no one he could talk to about the way his heart sped up when the ghost of his brother smiled.

It was beyond fucked up - he knew that. He knew that it was wrong on so many levels. But he hadn't been right for a long time, not since his brother had died and his ghost had held his hand and watched their parents cry. He'd made the decision years ago to centre his life around Sam; it didn't seem so scary to realise he was falling for him too. Just another leap of faith.

Dean trusted that Sam would catch him. He never had any doubts about that, not even for a moment. Sam had been catching him since he'd arrived back in his life, four years after his death - a constant support holding him up. Strong and beautiful and always smiling.

"We were never going to be normal, were we?" Dean whispered to Sam one night, tucked against his brother's barely-there presence.

"We could have been," Sam replied, and Dean was suddenly struck by the way he could see the wall behind his brother, see the bookshelf and the books and the music and the films. He could see it all because Sam wasn't really there. Not fully, not solidly.

"No," Dean muttered, turning to face the ceiling. "No, we couldn't've. Maybe if there'd never been a fire. Maybe if you hadn't died. Maybe."

"I'm sorry," Sam said, softly, after a few heartbeats of silence.

"Yeah." Dean blinked slowly, rubbing a hand across his face. "Yeah, me too."

Sam didn't talk for a while after that night, and Dean started to worry that maybe he was fading away. Sam was still there, a couple of steps behind Dean everywhere he went, but he stayed silent, just watching and listening.

Dean had never been scared of Sam before, but the silence freaked him out.

The threat of losing Sam had always been there. Everything Dean read about ghosts - because, once he was old enough to understand exactly what Sam was, he did a lot of research - suggested that once they'd fulfilled their final purpose then they would be able to move on. Whether that meant leaving to an afterlife or just ceasing to exist depended on your view of the world - but Dean had never been much of a theist.

They didn't know what Sam's purpose was. When Dean had mentioned it to him, Sam had gone blank and shrugged nonchalantly. Whatever happens, happens, he'd said. I can't control it.

Dean wished he shared that casual attitude - but when Sam did move on, it would be Dean who was left behind, Dean who was left alone. It was Dean who had pushed everything but Sam aside. And he wasn't sure that he could carry on without his brother.

It was the fear of Sam's fading away that spurred Dean to confess his feelings. He had put it off, hoping that if he ignored the emotions then they'd eventually just go away. But he'd never got what he wanted, and the world wasn't about to start then.

It came out easily, once he set his mind to it.

"I love you," were the first words he said to Sam on what would have been his brother's nineteenth birthday. "I've always loved you, and I think I always will. I can't see myself ever loving anyone else, and it terrifies me."

Sam just smiled, a translucent hand reaching out and hovering just above Dean's cheek. Dean swallowed and continued, slower this time.

"I don't think it's right anymore. The way I feel. It's gone past right, gone into wrong and bad and why are you smiling?"

"Why did you think I'd stayed for so long, Dean?" Sam asked quietly, his head tilting slightly to one side. "Why did you think I was still here, not resting in peace like I should have been?"

"Unfinished business," Dean replied automatically. "A purpose left unfulfilled."

Sam's smile widened, ever so slightly, and he nodded.

"You, Dean. You were my unfinished business. You were my purpose. It was always you."

Dean didn't understand - but, at the same time, he did. Because it suddenly made sense - how no one else had ever been able to see Sam, just Dean. How it had always been Dean that Sam spoke to, that Sam helped, that Sam kept company at night. It had always been him.

"You knew," he accused softly, eyes widening. "You knew and you never told me."

"You had to work it out. That was important. I think. You had to love me of your own accord, not because it was what I needed."

Dean let a small smile slip onto his face, then felt it drop off as a thought occurred to him.

"But now you've finished- now you've done what you need to do. That means-" Sam nodded again, once, his smile turning sad.

"I'm sorry," he murmured, "but I have to go now. I love you."

"You can't leave me, Sammy. You can't go. What do I do without you?"

"What you were always supposed to do, Dean. Live."

Sam pressed a soft kiss to Dean's lips, a kiss that Dean hardly felt.

"Goodbye, Dean."

Dean's eyes were filling with tears, his hands grabbing at Sam's body but passing straight through.

"Please," he begged, watching in horror as Sam's fingers faded from sight.

"Goodbye."

In the end, the decision to follow Sam was an easy one.

Buying the pills was easy, a matter of walking into the pharmacy and shooting the woman behind the counter his most charming smile. Building up the courage to take them was harder - but when he closed his eyes, he could see Sam's smile, and that helped.

The first mouthful were bitter, washed down with the strongest whiskey he could find. The next mouthful numbed his mouth - and after that he couldn't feel anything, just watch as the darkness closed in around the edges of his vision.

Sam was waiting, on the other side. He was still smiling that same smile, but now it was more solid - or maybe it was that Dean was less solid.

Either way, when Sam took Dean's hand, his fingers felt real; warm and fleshy and strong.

"Hey," Sam whispered, flashing Dean his dimples.

Beneath them, their parents sobbed, clutching onto one another as they mourned the loss of their second son. It was a tragedy, people would say. Two children dead. How can they cope?

"Hey," Dean repeated, squeezing his brother's hand as they watched their mother and father cry, just like they had all those years ago.