Author's Note: Thank you to immortal-jedi for doing a great betaing job! :)

Also, a reviewer let me know this story might need a tissue alert. It's hard for me to recognise this kind of thing in my own writing so thanks for the heads-up, TG! So yes, readers, you may want to have a tissue handy for this story.

"Dean, I've got a test tomorrow, can't we do this another day?"

Dean kept striding along, leading them further into the woods, away from the cabin they'd been squatting in.

"You need shooting practice," he said. "Dad told you that you had to practice at least twice a week while he was gone."

"How am I supposed to see the targets in the dark?"

After a moment, they finally reached the small clearing a little way into the woods. The shadows were darker here, only the gloomy light of dusk piercing the tree cover. They were well hidden in here, safe from the eyes of any busybodies going out for a late night walk. Not that there were any neighbors around the house, but you could never be too careful. Dean directed Sam to sit on a tree stump, and went over to place the beer cans on the wooden crates he'd set up earlier.

"There's still a little light," he said. "Besides, you need to practice shooting in the dark. You're 12 already; you'll be hunting ghosts with us soon. So this is good practice. Look, the beer cans are even shiny, just like the ghosts will be."

"Ghosts are shiny?" Sam asked skeptically.

Dean thought that over. They were more see-through white actually. He shrugged. "Close enough."

He pulled out the shotgun and cartridges from his backpack, and handed them over to Sam. He switched on his flashlight, pointing it so he could see what his brother was doing. "Yeah, so you put it-"

Sam slotted the cartridges into place and snapped it back efficiently, giving Dean an annoyed look. "I know how to work a gun, Dean," he said.

"Yeah, yeah." Dean switched off the flashlight. "Okay, give a shot, hot stuff."

Sam brought the gun up, squinting at the cans half concealed in the gloom and squeezed the trigger. There was a clink as the can on the far right toppled off the crate. Dean whooped and slapped Sam on the back. "Nice one!"

Sam managed to hit the remaining 4 cans with 7 shots, which was a respectable score, but he looked frustrated when he handed the gun over to Dean.

"That wasn't bad. No, really," Dean added as Sam glared at him. "It's your first time; you'll get better at it."

Sam looked away, a frown creasing his forehead. Dean grabbed him in a headlock and rubbed his knuckles over Sam's hair. Sam squirmed and tried to pull away as Dean mussed up his hair and laughed, before finally letting him go when Sam cried 'Uncle'. Sam straightened his hair, glaring at Dean.

"You're so childish," he said, before pushing past Dean.

They were picking their way through the undergrowth, Dean's flashlight lighting the way, when there was a sudden flash of red brilliance. Dean cursed, bringing his hand up to cover his eyes from the blinding light.

The light faded away, leaving a red after-image over his vision when Dean opened his eyes. He shrugged the backpack off, rummaging through it frantically. He pulled out the shotgun, loading it and bringing it up. He slowly turned on the spot, searching the woods for signs of movement. Sam was behind him, like he'd been taught.

There was silence, nothing, but Dean didn't relax, couldn't relax. Something was out there; something had made that red light. He was just readying himself to make a break for it when something pushed him, sending him flying forward, tumbling over and over. He heard Sam scream before he hit his head and everything went black.

There was something tickling Dean's nose when he woke up. He was lying on his front, face-down in the dirt. He pushed himself up, head swimming.

"Sammy!"

He slumped against the tree he'd been lying under, looking around the woods with blurry vision. It was completely dark now. He didn't know how long he'd been out; could have been 10 minutes, could have been an hour. He stumbled forward, his arms in front of him feeling through the velvety blackness. He almost tripped over something and he bent over to pick it up, relief flooding through him when he saw it was his flashlight. He turned it on, swinging the beam of light around. There was no-one there.

His heart was pounding now as he walked forward, carefully examining the ground. He was trying his best not to panic but he couldn't help running through worst-case scenarios in his head: Sam had been kidnapped by a monster, Sam was being tortured right now, Sam was already dead.

The pool of light landed on a scratched up area of ground. Someone had scuffed up the soil here, been dragged away. Then his eyes caught something that made his heart jump up into his throat. Blood. Speckles of blood were littering the ground, leading deeper into the woods. He swung the flashlight around, searching for his backpack, but it was gone. So was his gun. All he had was a switchblade tucked into his boots. He pulled it out, flipped it open, and started following the trail of blood.

His shoes crackled against twigs and fallen leaves with every step. He was surrounded by murky darkness; the only thing visible was the narrow path in front of him illuminated by the flashlight. After several minutes he realized where it was leading: a shack he and Sam had discovered soon after arriving here, long since abandoned, full of rusting tools and rotting logs of wood.

As he got closer he could hear a quiet sobbing and another voice, indistinct and low. He crept along the shack, grabbed a stone off the ground and pressed himself to the outer wall next to the frame where the door hung half off its hinges. He paused a second and then threw the stone, hitting a tree with a satisfying thump. The voice inside cut off, only Sam's gasping sobs remained. Dean stood still, waiting for the monster to come out to investigate. He'd slit its throat, stab it, grab Sammy—

"Dean."

Dean froze at the unfamiliar voice.

"Dean. Come in or I won't let you say goodbye to your brother," said the monster.

Dean squeezed his eyes shut for a second, not moving, and then he heard a strangled cry from his brother. He ran through the door before he was even aware of making the decision to move and halted at the sight of Sam, tears shining on his face and his head pulled back, knife held up to his exposed throat.

"Dean!" Sam choked out, chest convulsing in a sob.

The monster was standing behind Sam, holding him back in the corner. The darkness obscured it, only a vague outline of its frame and a shadowy face visible. There were dark smears of blood on Sam's shoulders and the monster's hands. For a second Dean thought Sam was hurt, but he saw the blood dripping to the floor and onto Sam's clothes, and he realized the monster was the one bleeding.

"Put the knife down and kick it over here," said the monster.

Dean swallowed, pausing before obeying.

"What do you want with him?" he asked, voice shaking only slightly.

"He needs to die, Dean."

Dean's heart was stuttering in his chest, he couldn't look away, terrified that he was going to see his brother die right in front of him. "He's just a kid," he said, forcing the words out through his tight throat.

The monster shook its head. "I didn't mean to go back this far. I was aiming for Stanford but I overshot. He's younger than I wanted but I have to. I can't let him live."

"Why?" Dean's words burst out. "He hasn't done anything!"

"You don't know what he's going to do!" shouted the monster, and Dean flinched at the sudden outburst. "He has demon blood in him and one day, he's going to destroy the world. There'll be nothing left, I've seen it."

Dean didn't even know what to say to that but he needed to buy some time. "How—how do you know what's going to happen?"

"I'm from that time. Everything's gone. He left me and I'm all alone." The monster's head dropped until it was almost cradling Sam.

"But you—, why would a monster want to stop someone from destroying the world?"

The monster laughed; a horrible, despairing choking sound. "I am a monster," it said. "But I'm your brother as well. And I have to correct my own mistakes."

Sam jerked involuntarily at this and the monster pressed the knife harder to Sam's throat, the edge nicking the skin. Sam stilled instantly, fresh tears running down his cheeks. Then the monster, still gripping Sam tightly, moved forward into the moonlight streaming through the door.

It was a man. A tall man wearing a white suit stained with blood and dirt. He had long hair, in just the kind of stupid style Sam would wear.

Dean took a step back, shaking his head wildly. "You're crazy! You're not my brother!"

"I am, Dean. And I missed you. It's been decades. I'm—I'm glad I got to see you before, before..."

The man gave a wobbly smile that looked painful. And try as Dean might, he couldn't help seeing his brother in that adult face.

"I don't believe you!" he yelled.

"I'm not lying," said the man. "But it doesn't matter whether you believe me or not." And he pulled Sam's head back sharply, knife held ready.

"Wait!" Dean screamed. Sam was whimpering, eyes squeezed shut. "You can prove it to me! And—and we can talk. You want to talk to me, right? I'll listen, just please, hand over Sam."

There was a terrifying pause as the man considered Dean's words, the knife just one slash away from ending Dean's brother's life. The man relaxed his grip on the knife.

"I do want to talk," he said slowly, before lowering the knife. "Here, take your brother. But don't run. I'll stop you."

He let go of Sam and pushed him forward. Dean reached out desperately and pulled Sam into his arms, feeling him tremble against his body. He took hold of Sam's hand and pushed him back behind him, shielding Sam with his body. He squeezed Sam's hand, signaling that they were going to try and make a break for it.

But before they could even move there was a screech behind them and Dean turned his head to see a cupboard full of rusting tools slide across the room all on its own, and block the open doorway. He swiveled his head around and saw the man still standing there a foot way, staring at the doorway. His eyes flicked over to Dean. Dean stood utterly still.

"I'm sorry," said the man. "I can't let Sam go."

"If—if you're Sam, then this is like killing yourself. Why would you do that?"

"I don't have anything left to live for. I let Lucifer possess me and he destroyed everything. The world is … it's just a garden now. An endless, empty garden." The man's eyes glazed over.

Dean shook his head emphatically. "I wouldn't have let that happen."

"Dean wasn't there. I was a mess, had been drinking demon blood, found out I was Lucifer's chosen vessel … I don't blame him for leaving."

"That's crap!" Dean shouted. "I'd never leave Sam."

The man smiled shakily. "I forgot he used to care that much. But no, he told me himself: he was done saving me."

Dean fell silent. He realized he was starting to believe more and more that this was actually Sam, though he couldn't conceive of how Sam had turned into this broken man. And he didn't understand how he would abandon Sam like that.

"He's—he's dead now," the man, Sam, said, with a hitch in his voice. "Lucifer used my body to kill Dean. He made me watch everything; everyone he killed and tortured. I felt it all but I couldn't do anything. When he went away some of his grace was left behind, and I'd learned enough from sharing his head to be able to come back here. And now I can stop him. If I die then none of that will happen."

Future Sam stepped forward and Dean backed away quickly. Sam cowered behind him, clutching Dean's T-shirt. "You don't need to kill him!" Dean said desperately. "I'll stop all that."

"You can't, Dean," said Sam in a cracked voice, and a tear slipped down his face. "Whatever you do it'll always end like that."

"I will stop it! I know now, okay. I'll save you, I'll save Sam."

The older Sam clutched at his hair, shaking his head. "No … I don't deserve to be saved. Please, just let me die."

Dean was almost there; he could feel it. He unhooked Sam's fingers from his T-shirt and edged forward, stretching out his hand to touch the man's arm. The older Sam let out a sob at the contact and fell to his knees, shoulders shaking. Dean knelt down carefully and took him into his arms.

"Dean," Sam choked out and gripped him back in a bone-crushing hug. Sam was shaking and letting out strangled sobs, like he was releasing all of his pain. Dean closed his eyes and stroked Sam's back, finding himself angry at the other Dean, that he had abandoned Sam like this.

"I'm sorry," he whispered.

Sam lifted his head and underneath the blood and tears smearing his face Dean could see his brother.

"You're my little brother," said Dean, and he gripped Sam's arms firmly, holding his gaze. "I don't know what that other Dean was thinking but I'll always—always save you."

Sam gave a watery smile, and whispered, "Thank you," his face relaxing like he'd finally let go of a weight he'd been carrying all this time.

Dean returned the smile, looking at Sam's pale face … which was growing paler by the second. Dean's fingers fell through the suddenly insubstantial body and he cried out in alarm. "Sam?" Sam just smiled back. Dean's hands scrabbled through the fading form of his brother, trying to grab onto him, keep him here, but Sam carried on fading, until there was nothing in front of Dean, only the bloodstains on the floor.

Dean stared at the empty space in front of him. His eyes were burning and he had to scrub the back of his hand over them. "Sammy." And then he was knocked back, his arms full of Sam, his Sam, crashing into him and hugging him.

"Sammy, he disappeared, I couldn't save him," said Dean blankly, his eyes unable to look away from the spot the other Sam had disappeared from.

"No, Dean, don't you get it?" said Sam. He was crying. "He disappeared because that future will never happen. You did save him."

It took a few seconds for that to sink in before Dean hugged Sam back tightly, holding onto the brother he had left. He closed his eyes and made a promise, to his little brother here and to the broken Sam from the future. "I won't let that happen," he whispered. "I'll save you, always."