/Author's Note: Hey all, I'm a recent addition to the Supernatural fandom and I haven't managed to watch all of the episodes yet – but the urge to write was impossible to resist! This is based on the conversation Dean and Sam had in S2E10 'Hunted', where Dean reveals what their father had told him before he died. I wrote it before watching the rest of the season, so if there are any inconsistencies that's why. Thanks for reading! Enjoy :) /

Stop Me

Sam huffed out a mirthless laugh, his expression caught somewhere between disbelief and horror. "Dad told you to kill me," he echoed dully.

"No," Dean said, quick to defend the memory of their father. John Winchester was many things – a soldier and a hunter first and foremost – but he was not a monster. "No, he told me to save you."

"Yeah? That's real helpful – makes me feel loads better." Sam's sarcasm was harsh, biting. "Save me from what? Save me from doing what? Becoming what? He knew, didn't he – he knew the plans this demon has for me – but he just decided to keep it to himself!"

Dean's gut clenched hearing Sam rail against their dad, a lifetime of arguments he could never seem to stop flashing through his mind. Then Sam rounded on him, jabbing an accusing finger in his face. "And you! You were never going to tell me either, were you?"

Dean pushed Sam's hand away and tried to keep his voice even. "I've told you now." He thought it would be a relief to get this weight off his shoulders, but far worse than having his father's last words haunting his every waking moment was seeing the fear and betrayal in his little brother's eyes.

"Oh, that's great, thanks," Same said bitterly. "And were you going to give me a heads up before you commit fratricide or were you going to let my imminent murder come as a surprise?"

"I'm not going to kill you," Dean growled, clenching a fist but battling the urge to lay his brother out for calling him a murderer. "For Christ's sake, Sam, my entire life has been about keeping you safe. I'm not about to go and blow all my hard work." He tried to smile, to inject a hint of levity into the situation, but his brother was having none of it.

"You're a hunter," Sam shot back. "You kill evil things for a living. Why should I be any different?"

"Stop it, Sam! You're not evil."

"What if I were?"

The silence that followed his words was deafening.

Dean should have been able to snap out a witty comment, something funny or sharp or at least dismissive, but the words wouldn't come. Because for the past couple of months he had been asking himself the very same question.

When Sam finally spoke again, his voice was quiet. "What would you do, Dean? If I really was evil. If I started killing innocent people."

"You wouldn't."

"But if I did. Could you do it, Dean? Could you kill me?"

"Don't ask me that!"

He wanted to storm away, to get back in his car and drive and keep driving as if distance alone could make all of this go away, but brown eyes had him pinned.

"Dean."

"We are not having this conversation."

"I want an answer."

"That's tough!"

"Tell me, Dean."

"Why the hell do you even want to know?"

"Because I'm scared!" Sam blurted.

Dean stared at him, wide-eyed.

"I'm scared, Dean," Sam said again, and his voice cracked on the words.

It was a rare confession; one that had rarely been uttered aloud since a trembling Sammy, three years old at the time, had whispered it in Dean's ear as they hid together in an old wine barrel, listening to inhuman howls and grunts of pain as their dad battled some demonic creature just outside. Dean had been frightened too, but he would never show it. He was Sammy's older brother, and he knew the responsibilities that went along with the role.

"Don't ever be scared, Sammy," Dean had said. "I'll always keep you safe."

"You promise?" Sam had sniffed.

"I swear on my life," Dean promised solemnly.

He had meant it. He still meant it. And Sam should damn well know that by now.

"Scared of what?" Dean asked hoarsely. "Scared of me?"

"No." Sam looked away, as though he were ashamed to say the next words. "Of me."

"What? Why?"

"I don't know what I am turning into, Dean. I don't want to become something I'm not."

"You won't."

"We don't know that! If I start killing people, Dean, or – or worse, I need to know that you'll stop me."

"Of course I will."

"No, Dean." The steely gaze of his brother was back, razor sharp and deadly serious. "I mean stop me."

"You mean kill you," Dean translated bluntly.

Sam swallowed, but the resolve in his expression did not waver. "Yes."

"Christ, Sam," Dean swore softly. "You're unbelievable. How could you ask that of me?"

"Dean, please. You are the only person I can trust to do this." He was using The Face, the one that got him anything he wanted, the one nobody could say 'no' to. "I'd rather die than turn into a monster."

Dean knew it was true. For all that Sam had been raised from an infant to be a hunter, he had never relished in the killing or taken pleasure in the job beyond feeling the satisfaction of saving lives. Sam just had a gentle spirit. He was never meant for a life of violence and bloodshed. Dean wished more than anything that his little brother could have had a normal childhood, untouched by hardship and tragedy, but he couldn't change the past. The only thing he had any control over was the future, and yet Sam was talking like his fate was already set in stone… like Dean's only choice would be to kill him.

Sam wanted Dean to kill him.

"You are a selfish bastard, you know that?" Dean snapped. "It's always all about you, isn't it?"

"This isn't about me," Sam protested. "It's about protecting people."

Protecting people. As if any one of their lives was worth more than Sam's.

Hadn't they already sacrificed enough? They had given up home and friends and their very identity to live their lives helping others. Now Sam had to die, for people they didn't even know, didn't even love?

The damn burst.

"The only person on this entire planet I give a damn about protecting is you!" Dean thundered. "You think I do this job because Dad ordered me to? You think I do it to avenge mom's death? You think I do it for the thrill of fighting or for those helpless, hapless civilians whose lives we save? None of that matters to me – none of it! Not without you. I pulled you from that fire when you were a baby and ever since then the only thing I have ever cared about is keeping you safe. The only thing, Sam. And if I can't do that…"

Dean struggled to maintain his composure, desperately fighting the tears that threatened to well up in his eyes. He wasn't going to cry, damn it.

He tried to keep arguing, but the words stuck in his throat. He turned away, not wanting his little brother to see him so weak.

"Dean… I'm sorry."

He drew in a slow breath. He needed this conversation to end and for them to never speak of it again, but he knew Sam would not let it go. "Sammy, I need you to understand something." Heart-to-hearts were not his forte, but hell, they had already come this far. "Are you listening to me?"

Sam nodded wordlessly.

Dean closed his eyes, gathering his strength, then forced himself to meet his brother's concerned gaze. "Sam… If you die, I die. It's that simple. So you want me to kill you if you go dark side? You know what – fine. I never could deny you anything you wanted. But if you force me to shoot you then I swear to God, Sam, the next bullet will be for me."

"Wh- No! Dean, you can't-"

"You won't be there to stop me," Dean reminded him, his tone flat.

"But Dean, you're stronger than that. You could go on fighting," Sam said desperately. "You don't need me!"

The Demon had known differently. Strange that Sam didn't. "That's where you're wrong."

"Dean, please. Don't make me responsible for…" Sam trailed off, realising the hypocrisy of his plea.

"My death?" Dean finished for him, driving the point home and making Sam flinch. "Well you know what the solution is, Sammy. Whatever it is, whatever the Demon has planned for you, bloody well fight it."

Sam swallowed nervously, but Dean was glad to see that the resolve had returned to his eyes. "I will. I promise."

"I'll hold you to that, Sam. And if I mean anything to you, you better make damn sure that I never have to make good on mine."

Sam nodded.

"Alright. Then we'll be fine." Dean said it with more confidence than he felt, and Sam did not look entirely convinced, but at least for now the discussion was over.

They returned to the Impala. Dean blasted the music loud, and for the next few hours neither of them said a word. Dean's eyes remained fixed on the road ahead and Sam gazed blankly out at the scenery flashing past. By unspoken agreement, when they reached the next town they made a beeline for the closest bar.

The two brothers drank until they couldn't see straight and kept drinking until Sam passed out and Dean was kicked out lugging the weight of his not-so-little brother with him. They were warned in no uncertain terms never to come back, and the next morning their hangovers would leave them looking like zombies and feeling worse.

But for one night, Dean was able to forget the unbearable request Sam had made of him. For one night, Sam was able to forget that Dean had given in and committed himself to a murder-suicide if Sam ever went dark.

Unfortunately, reality returned with the dawn.

But they went on with their lives, hitting the road, moving on to the next town, searching for the next hunt and fighting the next monster. Though the conversation lingered in their minds, they never spoke of it again.

The whole thing was based on a hypothetical scenario anyway. It was never going to actually happen.

Or so they hoped.

Fin

/Author's Note: Thanks for reading! I hope you enjoyed it. Don't tell me what happens, I'm almost up to the end of season 4 now but no spoilers please! Can't wait to see what happens next :) /