The Last Mistake

Summary: After learning that Roy & Walt jumped Sam while he was in Purgatory, Dean goes solo to keep a promise he made years ago. When things go bad with an unexpected betrayal, can Sam find his brother in time to keep this act from being someone else's Last Mistake? /Angsty/upset/hurt!Dean & Slightly hurt/upset/Sam… and a guest shot by a helpful Garth.

Warnings/Spoilers: Language. I'll warn for that and for some damage to the boys but nothing that will tip the graphic scale. It will have spoilers from 08x14 Trial and Error.

Tags: Not to an actual episode but this is a carry over from my other tag to 08x14-Trial and Error that's titled, 'You're Not a Grunt, You're My Brother.

Disclaimer: I don't own the boys or anything to do with the show. This is written for my own enjoyment and for the enjoyment of other fans.

Author Note: I'd planned to do this for a while but I've been putting it off until the last story, 'You're Not a Grunt, You're My Brother' took the turn it did and made it pretty clear that Dean needed to handle Walt and Roy. It's a semi-sequel, as it comes after that story but can be read as a 1-shot I think if someone just comes across this without reading the other first. I hadn't planned on it being a chapter story, but again not even authors can fully control the plot. So read and enjoy.

CHAPTER ONE

South East Lousiana:

"Yeah, this looks promising."

Dean Winchester had certainly been doubting some recent choices and while he didn't doubt this one per se, he did just slightly wish he would've asked for a bit more details on where the hell he was going actually was located.

Double checking that his weapon was loaded and easy to access, he checked to be certain he had other things before making sure the Impala was parked far enough back in the heavy brush that it wouldn't be seen and then just prayed that it also didn't sink in the way too soft dirt.

"Sorry, baby. Y'know I wouldn't leave you here normally but this is for Sammy," he spoke softly to the car without thinking how strange that might seem to others.

Letting his hand run over the roof one last time, Dean's green eyes took on a harder look when he turned to stare off at the distant, overgrown muddy path that, according to his source and the very reluctant locals, would lead him to his ultimate destination.

He'd known he'd be heading deep into bayou country for this gig but he hadn't been expecting the damn cabin to be on some overgrown and abandoned old sugar cane plantation that was close to being reclaimed by the swamps and its own inhabitants.

Dean hesitated then blew out a breath. This had been coming for close to three years and after what little he'd pulled from his brother and the minimal amount of details that Jefferson had added when Dean had cornered the older hunter on the phone three nights ago he knew he would not put off what he should've handled the moment he and Sam returned from Heaven after the bastards shot them.

"Sorry, Sammy," he whispered, knowing his younger brother would more than likely be pissed when he figured out what Dean was doing since this reaction was one of the reactions that had kept Sam from telling Dean the truth behind Sam's dropping out of hunting for the year that Dean was trapped in Purgatory.

A hunter for the biggest part of his life, Dean had been killing evil things and looking after his little brother for as long as he could seriously remember. Well, he knew he'd been looking after Sam longer than killing evil sons of bitches like witches, ghosts, etc, but this was one of the few times that while he was hunting evil, this evil wasn't of the supernatural kind.

A quick glance at a hand drawn map showed him about how far into the plantation the tiny old cabin was from where he was so Dean guessed the best way to approach would be. He figured he'd handle the rest once he got there because while he wasn't big on killing humans, he had done it before and he'd made a promise three years ago that this last mistake had just hastened.

Not big on swamps or bayous to begin with, the soft ground and heavy growth of trees and weeds were making Dean's nerves more on edge than he liked. He had no doubts that the odds of his arrival being unexpected were slim since the small community he'd arrived in seemed more afraid of the one man he was hunting than the legends of this place being cursed or hunted.

The low sounds of the night were all the hunter heard but the further he went the more he thought back to what had sent him on this solo hunt.

Three nights earlier he'd finally learned more than he liked about what his brother had been up to while Dean was in Purgatory.

Since his return, Sam had let Dean bitch and gripe that Sam had simply walked away right after he'd vanished. He took the bitterness and jibes that he hadn't even bothered to look for Dean, that he'd simply walked away, hit a dog, met a girl, and settled into a normal life.

This is what Dean believed because this is what Sam had basically led him to think…until the other night when finally, after all the strain and stress of recent months, of killing a damn hound of Hell to kick off the three trials to shut Hell once and for all, Sam's emotions got the better of him and it all came out.

'Sure, I had to poke and prod to get some of it,' Dean thought to himself sourly, still seeing the haunted look in Sam's too huge hazel eyes when he realized he'd said too much and his suddenly very intuitive big brother had caught on to things he hadn't wanted him to know.

A huge part of Dean had always known that something had been off. He'd practically raised Sam. He knew his brother like the back of his own hand and knew how the kid reacted to things. So for Sam to just say he quit and that was all, the big brother in Dean reacted faster than the side of him that did actually have common sense.

So while he'd been hurt that Sam said he hadn't even looked for him, that other side knew there was another side to that lie. He just needed to wait for Sam to eventually give it up because as Dean knew well, his brother had learned to lie to him pretty well…he just couldn't do it very long.

That night Sam had gotten tired and too emotional so he hadn't been watching either his tone or the unspoken words that he should've known his brother would pick up on and eventually he'd revealed the three months that he had looked for Dean.

"Three damn months and then he gets set up," Dean was pissed as it was about that even though he knew that Jefferson wouldn't set his brother up on purpose, he was still suspicious enough to be leery now…especially now.

Dean knew how Sam was and could see it play it. Three months of dead leads, fallen hope, and being alone since before, when Dean was in Hell, Sam still had people he could depend on. This time, he'd been basically solo and when the lead came from this tiny little hellhole he'd jumped at it and didn't see the trap until it was too late.

Three years ago, it had gotten out to the hunter community about Sam and Dean's roles in opening the gate to release Lucifer and jumpstart the whole Apocalypse.

While Bobby had done his best to smooth it over, to explain what he could without giving away the nitty gritty details, namely Sam's addiction to demon blood and the abilities it had once given him, there were hunters who held a grudge. Hunters who didn't see Sam as anything different than what they hunted.

Dean knew his little brother had encountered a few of those while they'd been hunting solo for a short time. "Which reminds me that he still hasn't come clean with me about some of that," he muttered, reminding himself to keep that for a later time since he could now see a low light coming up in the distance which meant the cabin was getting closer and so was his prey.

Between the looming Apocalypse, having two Archangels wanting to ride them as cheap suits, and every other problem pressing a wedge between them, Dean accepted that things hadn't been good.

He'd been on a downward spiral with self doubt and plenty of doubts about Sam when he'd drank himself to sleep one night in a cheap motel only to wake up to two morons with weapons aimed at him and Sam.

The fact that some stupid son of a bitch was pointing a gun at his brother had woken Dean up fast. Then the fact registered that he actually knew the voices under the masks pissed him off more.

Running afoul of strangers were one thing but he actually had known these jackasses, had known that they'd hunted once or twice with his Dad and that made him madder.

His reaction time was off and but Dean had still hoped to draw Walt's attention off of Sam so that maybe his brother would have a chance since Roy had never been much of an issue but to this night Dean could still hear the sound of that shotgun blast that tore through Sam, could see his brother lifeless on the bed.

"'When I come back, and I will come back, I'll find you,'" he'd made that dark promise a moment before the gun fired again and he found himself on the back side of Heaven, looking for Sam and avoiding that damn bald Angel.

Coming back, things had gone from bad to worse so he'd never had the chance to actually keep that promise. Since then, Sam had been locked in a Cage with Lucifer and Michael, had been without a soul and nearly beyond Dean's control and had nearly gone mad.

Dean figured he'd been a little busy to consider paying the two morons who'd killed them a visit and probably they would've stayed off his radar if he hadn't learned one thing…

If he hadn't learned that Walt and his little cohort in crime hadn't decided to be wiseasses and jump his little brother. Even that might not have pissed Dean off to the extent that he would've left Sam on his own back at their new base in Kansas to come to the bayous of Louisiana to keep a promise he'd made three years earlier.

Fist clenching in a rage that he rarely had felt this much, Dean could just close his eyes to see the scars still on Sam's upper back and shoulder. However, it was the brand that had been cut into his lower back that had made this visit a certainty and would make that the last mistake of Walt's life.

Noticing as he slowly got closer that the battered old truck that the waitress back at the diner said Walt drove appeared absent, Dean scowled.

He'd left Sam with the excuse of checking in on their resident prophet/geek Kevin to see if he'd figured out what the second trial would be. That had been three days ago.

Dean didn't like leaving Sam on his own right then as a general rule because he wasn't sure how his brother was handling things since he'd seen him favoring his right arm more than once since killing that hellhound.

Sam had been on edge the morning Dean had left but he'd shrugged that off to still being emotionally wrung out from the night before and his concern over what his brother would eventually say to him or, in this case, eventually do.

He had no doubt that by now Sam had clued in on Dean's plan. If he was gone any longer he knew his little brother would start backtracking him and Dean did not want Sam down in the tiny Louisiana town nor did he want his brother any closer to Walt and Roy than he needed to be.

"As in at all," Dean decided firmly, refusing to let either of the sons of bitches near his brother.

Taking another look at the front of the run down, little cabin that he figured must have been an overseers cabin from its position on the former plantation.

A deep set sense of caution warned him to go slow, to do this by the book. The feeling of eyes on him should have been telling but Dean shrugged that off as listening too many old stories in town earlier that morning. He did take the time to circle the cabin once to look for another door or to be certain Walt's truck wasn't parked behind the building.

Not seeing the truck and not seeing anything that told him differently, he stayed in the shadows as he finished his circle to notice a window toward the front of the cabin that gave a pretty clear view of the place.

"Clear view in, clear view out," Dean muttered, those warning bells beginning to go off a lot louder. He saw Roy, the smaller, skinnier of the duo, pacing the cabin as if restless or… "Waiting for something."

Dean Winchester had been accused of a lot of things in his life and hell, he copped to most of it, but never to willingly walk into something that was beginning to scream like a bad move. "Damn it, Jeff," he swore under his breath while trying to ignore the pain that this possible betrayal gave him.

Deciding it best to take a step back, retreat to the Impala and a safer spot to think and maybe, just maybe, call Sam, Dean had gone to turn when his eyes caught sight of something piled under a pile of tossed brush. "What the hell?"

Not stupid by any means but too curious at times, Dean used the barrel of his weapon to push it aside to see that mostly it seemed to be trash, old food containers, moldy food and some spent shell casings.

"Assholes," he whispered, knowing one of his Dad's first lessons had been to never leave anything behind that could be traced back to you.

He was about to follow the advice of his sixth sense and get the hell out when something else grabbed his attention and he felt his jaw clench.

"Sonuvabitch," flicking some trash aside, his fingers touched material that seemed stiff but as he pulled it closer to see the amount of dried blood on the worn flannel shirt that he'd asked Sam about when he'd gotten back from Purgatory.

Sam had tossed off some excuse about the shirt getting oil or something on it and he'd had to toss it out. Now as Dean's fingers clenched around it, he felt the dried blood, found more than a few shreds that were reminding him why he was down here when he touched something in the pocket and once again saw red.

The black rubber bracelet had been something they'd both once had. Dean had finally given Sam back his after he'd gotten out of that mental hospital after memories of the Cage and Lucifer had nearly killed his little brother and Sam had been wearing it that last day when they'd faced down Dick Roman.

It had just dawned on Dean the other night while his cranky and pissed off little brother had been poking him in the chest that Sam hadn't had the bracelet and now, as he drew it from the pocket of the shirt, he knew why.

Setting his brother up to be jumped was one mistake. Putting hands on him, hurting him in any way, shape, or form, was another mistake but to take from him one of the few things Sam had left in his life that meant anything to him, well to Dean those were mistakes that would be handled very slowly and very seriously until the hunter in him snapped back to the front.

He'd been in Purgatory a year. Sam was jumped by the Dynamic Duo of stupidity three months into that. That left seven months plus the few since Dean's return to get rid of this crap when it looked like it had just been tossed recently.

"Shit, shit, shit!" realization hit a second before sharp and brutal pain slashed through his skull as something hard crashed down on the back of his head and he fell to the wet ground with a sick feeling that got worse as a hard boot cracked a rib. "Ugh!"

"Well, well, well, you look pretty good for a dead man, Winchester. Though I guess you're pretty good at coming like that," the voice was as familiar to Dean's ringing head now as it was three years ago. It just sounded tinier due to the pain he was in.

Rolling onto his back, Dean managed to cut off the next grunt as another kick hit him hard before the boot pinned his gun hand into the mud and kicked his Colt away before kneeling over Dean with a sneer.

"Heard you were coming, Dean," Walt grinned, seeing the bloodied shirt and smirking again. "I told Roy keeping that piece of crap would come in handy. You here about that message we gave Sammy?"

In pain and barely able to see with the throbbing behind his eyes, Dean still wasn't going to give this son of a bitch the satisfaction of knowing that. "It's…Sam," he gritted, still refusing to let anyone else call his little brother by the nickname that Sam only let him use. "Screwed…up, Walt," he gasped out as he felt his wrist ache under the weight of the boot. "Promised you'd…see me again and…you never should've touched…my brother."

Amused at this, the much shorter but stockier hunter laughed, deciding this night was going to be more fun than he'd counted on as he considered the short but fat piece of polished oak he'd used to crack Dean's head open with.

"This time when I kill you, I'll make damn sure you stay dead, Winchester and then Roy and I'll finish what I started with your brother," Walt vowed, giving the oak bat a hard swing down.

Eyes clearing enough, Dean had a short time to see the weapon aimed at his head before pain and bright lights exploded again and his consciousness drained away with thoughts of Sam and the idea that this plan better work before everything went dark with just Walt's sickening laugh in his ears.

TBC

A/N II: I know, I haven't down an actual chapter story in awhile (yes, I will finish Fractured Family) but CH 2 will be up very soon. Yes, I also know I'm still evil to leave it here. Dean's in deep, Sam has no clue to where his brother is and can he find out before it's too late? Stay tuned.