A/N: This was written for the wonderful Phx, whose work I admire almost as much as her friendship. And if you haven't read her fiction, why the hell not? She's listed in my favorite authors: read her fiction. You will not regret it, trust me.

"You're kidding me."

Bobby merely raised his eyebrow. Sam snorted behind his hand, and Dean continued to stare. "Scientists are going on and on about huge frickin' machines, and time travel exists in a rock?"

"You gonna take it or what?" Bobby asked, holding his arm out further.

Sam's smile faded away at that. "What are we supposed to do with it?"

"Use it."

All other incredulities and jokes from Dean were firmly squashed. "Bobby, no," Dean said, voice quiet and firm. "We need to destroy it."

With a sigh Bobby leaned back against his truck, rock still in hand. Damn thing had been hard enough to find without adding temptation to the mix. Dean could instantly call up several key moments he'd jump back to, and Sam looked like he'd been smacked by a two by four with the possibilities.

"You can't destroy it," Bobby said, his gruff voice almost gentle. "I'm sorry, boys. Pick something small and jump back. Make it significant enough that the stone has a purpose, but not significant enough to change something." He made a face before tossing the stone at Sam. Sam caught it purely on reflex, then winced as if he'd touched something slimy. "Better you use it on something small than have someone else get a hold of it and end the world in 1865," Bobby muttered.

Sam still looked like he'd been slapped. Hard. "Use it before you lose it," Bobby warned, stepping into his truck. Dean watched him go, wondering exactly when they'd gotten the hard part of hunting. It used to be Bobby and their dad, taking care of things.

God, Dad-

"Let's go," Dean said gruffly, turning and leaving Sam clutching the stone. "We'll think of something back at the hotel."

"How about something that involves us pitching the rock to join the other rocks down that hill," Sam said, and Dean turned back with a glare.

"No. Trust me, I want to, too, but Bobby's right. Last thing we need is for someone to pick it up to skip it in a pond and think to themselves, 'Gee, wish I could've seen this place when it was an ocean'. And as a result, cause dinosaurs to live in our time."

"Yeah, because that's the worst thing that can happen," Sam snapped. Dean ignored him and slid into the driver's seat. After a moment of standing and glaring, Sam finally stomped around to his side of the car and got in, slamming the door as he did so. The car was tense and silent.

Dean finally sighed and admitted, "Look, you want to do this as much as I do, but let's just grab something easy that's not going to affect the future. Like, we'll go back in time to yesterday and pick up the cheeseburger wrapper I tossed towards the trashcan and missed."

"And cause someone to not pause later as they picked it up, and then get killed walking across the street when they would've avoided it before," Sam finished softly. He still looked tense, though, despite the tone. "Whichever one of us uses it, the other won't remember. And it'd be better if we did something in the past that affected the other. Something small, but since we're both here in the present, there's less chance of us messing with each other's time lines. It'd be...easier for us."

Dean pursed his lips but nodded. Easier, his ass. "Then start thinking," he muttered, turning the key in the ignition. "We've got about twenty minutes back to the hotel."

"What do you regret most?"

Sam slowly turned to Dean, his gaze incredulous. Dean looked pensive and thoughtful himself, and it was for that reason alone that Sam took a breath before answering. "I think the easiest answer most days is what don't I regret," he answered dryly.

"Not the obvious stuff," Dean said, and Sam didn't miss how his brother swallowed painfully. Sam'd been choking down a few knots of his own ever since Bobby had tossed the rock his way. God. The thought was so tempting to just go back and make it all right. Dad, Jess, Mom. Someone Sam had only put to pictures, never to touch or sound until last year.

They couldn't chance it, though. Couldn't chance screwing up the future for just one right choice in the past.

If he couldn't save lives, then...he closed his eyes and tried to think about the thing he regretted the most. Not calling his dad while he was at Stanford, obviously. Not calling Dean at Stanford. Not saying goodbye, arguing and constantly pushing to leave.

"Stanford," he said, and when he opened his eyes, Dean was gazing at him with surprise.

"Stanford? Are you serious? I didn't think you regretted going."

"Not going," Sam corrected, "I needed to go. But...the way I went. I just regret that I didn't tell you goodbye."

Dean snorted and gave a wry grin. "Then next time, make sure you leave a note or something."

Sam inhaled sharply, his stomach twisting. Wait. But... "What?" Dean asked, already wary. "What'd I say?"

"I did leave a note," Sam said softly, and it was his turn to swallow hard.

Dean's jaw slid down. "Then where the hell did you leave it? I told Dad you'd left one, that you wouldn't have left without one, but I couldn't frickin' find it-"

The twisting feeling in his stomach intensified. "Dad," Sam managed faintly. "I...I gave it to Dad to give to you."

Dean froze and stared at Sam. Sam stared back, feeling hurt and stupid and a million other emotions. Dean had never gotten the note with the goodbye and the phone number for Sam's new cell phone, the dorm address, the bus time to say goodbye. Sam had waited for almost an hour for his brother to show at the stop, waited and waited and had finally boarded, feeling more alone than he'd ever felt before. He'd thought that Dean would've come, and then his big brother had abandoned him. Sam had taken the message to heart, and the two times Dean had called looking for him, he'd told his roommate he was unavailable.

If Dean had never gotten the message...

"I thought you didn't want me in your new life," Dean said softly, and Sam flinched. His attitude at school certainly hadn't helped any.

"I thought you agreed with Dad, and you didn't want anything to do with me," Sam admitted. "My bus didn't leave for another hour."

"You sat and waited for me," Dean said, and the stunned words were laced with sorrow. Sam met his gaze briefly, then looked away.

Water under the bridge. What was done was done.

Except where that time stone was concerned, and Sam's head whipped back around to Dean. Dean, who was already gazing at the rock with too much determination. "Dean. No."

"C'mon, Sam," Dean said. "The hell else are we supposed to use it on? You wrote other things in that note, didn't you?"

"That's not the point," Sam said firmly. "If you meet Dad and confront him over the note, you could change things. Set things into motion that would lead to one of us getting killed or something." His head was starting to hurt just thinking of the logistics of it, and he pinched the bridge of his nose.

Dean sighed and slumped forward. "Fine. Whatever."

Sam's hand fell away, and he bit his lip. "I hated not thinking I could contact you when I needed to, that I couldn't talk to you because..." He cleared his throat and kept going. "But you and I, we're here now. That's what matters, isn't it?"

A pause followed, before Dean raised his head. "Yeah," he said quietly. "We're here now. We'll just...figure out what else we can use the stone on." His eyes lit up suddenly. "Lottery num-"

"No, Dean."

Sam was out like a light at an early hour. Dean stayed awake, feigning sleep only until he knew for certain that Sam was asleep. They'd agreed to try the stone tomorrow, sleep on a few of the ideas and then make their decision.

Screw that. Dean knew what it had to be used for.

And honestly? He didn't really care if it changed the future. The only way it could possibly change things was for the better, and after the revelation of earlier...he had to. He'd lose his big brother license if he didn't.

He carefully grabbed the stone and tip-toed outside, going beyond the car into the parking lot and stopping. The stone was cold and smooth in his hand, and it smacked against his palm when he tossed and caught it.

Probably should've asked for the directions on how to use it, but oh well. Dean Winchester didn't need directions. Besides, the most difficult thing he'd ever had to work with and figure out was Sam, and the kid sure as hell hadn't come with instructions.

Dean closed his eyes and grasped the stone tight in his fist. "I wish I was back on that day when Sam left for Stanford." The wind rustled, and he kept his eyes clenched shut. After a moment, he dared to peek, and frowned when all he saw was the parking lot.

"The hell...?" Fine, he'd try something else. He clasped the stone in the opposite hand and closed his eyes again, focusing on the memories of that day. Of coming back inside, finding his dad standing alone in the middle of the room, looking sorrier than Dean had ever seen him. Of him wildly and frantically searching the room, tossing blankets and pillows in a desperate attempt to find the note he knew Sam had left for him. Of storming out into the hot day, feeling shaky and hurt and frustrated and lost-

And suddenly, it felt a lot warmer out.

Dean opened his eyes again, but this time, the blinding sun above him made him wince and cover his head. "Whoa," he muttered, almost falling off the stairs in front of the small house. The house they'd been renting when-

Oh god. His dad was inside, right now, right behind him, and Dean tightened his fists until half-moon bloody ridges were embedded in his skin. No. No no no. Only interact with Sam. Because Sam was still a known variable in the future, but that still didn't make sense in Dean's head, but it did in Sam's, and his head was going to hurt even more if he didn't stop thinking and start doing.

Sam. He had to get to Sam.

Instead of driving around aimlessly in his car, as he'd done the last time, Dean slid into the front seat of the Impala with purpose. He pulled out much the same way as he had before, and wandered down the same streets he had before.

This time, however, he made a cautious turn when no one was around and made his way down towards the bus station. He parked away from everyone, completely invisible, and made sure to keep to himself. No bumping into anyone, no eye contact, no talking.

Wasn't all that hard. He was a little focused on what he'd actually say to Sam.

He finally found him, under an awning with his duffel bag, and Dean had to stop and stare. Sam was young, painfully so, and Dean couldn't believe he'd let Sam go at so young an age. Hair was everywhere, as usual, and the same brooding look was on his face.

The tears weren't new. As much as Dean hated seeing them, they weren't a new sight, either. The hoodie was Dean's, and still a little too big for Sam, and Sam sniffled and wiped at his nose with the sleeve.

"Sammy," Dean managed, and Sam's head whipped around at his voice. His eyes lit up, and the hope and relief in his face was enough to make Dean want to cry. Sam bounded off the bench, almost tripping over his duffel bag in his haste to get to Dean.

"Wasn't sure you were gonna come," Sam admitted, stopping in front of Dean. "I mean, I know I told you in the note that I needed you to be here, but...I dunno. Dad was pretty pissed. I figured you'd be pissed, too."

I needed you to be here. No wonder Sam had never been 'available' when Dean had tried calling him at Stanford. Dean winced and reached out, clasping Sam's shoulder under his hand. "Not really pissed. Upset, yeah, but...but I saw it coming," he admitted quietly. And he had. God knew he had from the day Dean himself had been shown pamphlets of colleges around the nation. They hadn't really tempted him, not really, but Sammy? He'd known Sam would be tempted.

Which led Dean to his next point, before Sam started looking too miserable again. "But I'm proud of you," he said, pulling Sam in close enough for their foreheads to bump. He looked straight across into his little brother's wide eyes and smiled, saying everything he'd wanted to say for years. "I am so proud of you. Full ride, man. You don't scoff at that. And Stanford. That's a hell of a thing, Sammy, and I'm proud of you. Always have been, always will be."

Sam's eyes were filling with tears again, his breath coming in tiny hitches, and the look on his face said he'd finally realized he was leaving Dean behind. They were saying goodbye. Dean wanted desperately to tell him it wasn't permanent by any means, that in a few years they'd be back together, but he bit his lip instead. "You're gonna do awesome things, I know it," Dean managed, and if his stupid throat didn't stop closing, Dean was going to have to do something drastic. Like make a pass at the nearest girl, and right now, he couldn't afford to do that.

Stupid time travel.

A bus pulled up and slowed to a stop near the bench Sam had been sitting on. Several people began heading for the doors, and the brothers spared it a long, knowing look before turning back to each other. Sam swallowed and swallowed again. "Dean-" he choked out.

Dean gave him the best carefree grin he could. "You'll be fine. You can do this, Sammy. I know you can." He paused, thinking it over for only a moment, before saying, "And I'm only a phone-call away, okay? You can call me anytime. You know that." Okay, that was possibly breaking time-laws and destroying the future in some complicated way Dean didn't understand, but hey, if it was something Sam already knew, then it couldn't hurt that much, right?

"You can call me, too," Sam said, before he wiped at his eyes. "You know that too, right?"

"Damn straight," Dean said, and Sam finally grinned, tears and all. "Now if you don't move your ass, college boy, you're gonna miss the bus."

Sam nodded and pulled away, giving a quick wave before walking to haul his duffel up. He slung it over his arm and headed for the line of people about to board the bus, then stopped, eyes on his feet. He turned and ran back for Dean, duffel flying behind him, and Dean had his arms open in time to catch his little brother flying at him. "You can come see me," Sam whispered. "Okay?"

Dean swallowed and hugged him tighter. "I know. I know, Sammy."

They finally parted, and Dean ruffled Sam's hair for the hell of it. Sam ducked out of instinct, then gave as bright a smile as he could manage and headed once more for the bus. This time, he boarded, his eyes constantly darting back to Dean.

And when he took his seat on the bus, he took a window seat, eyes glued to Dean. Dean stayed where he was standing, hands in his pockets, eyes on Sam. The bus closed its doors and began to move away from the station. Dean began to smile and kept it until the bus had faded into the distance. He closed his eyes and took a deep breath, still smiling.

A beeping sound made his eyes open frantically, and he frowned, taking in the alarm clock in front of him. "The hell...?" he said.

"You set it, and you're surprised when it goes off. Genius, Dean."

Dean flipped over from where he was apparently laying down to the other bed, where Sam was sitting up, stretching and yawning. "I told you to let me set it," Sam said, but he was grinning, and Dean grinned back. Same hotel from earlier, same sheets, same older Sam.

And the stone was gone.

"You always put it on some pansy-assed station," Dean grumbled, and Sam leaned over to give him a mock-punch. "You snagging first shower, or am I?"

"You are," Sam deadpanned. Dean leaned over and pinched, and Sam chuckled and slid away. "What are you, two?"

"Takes one to know one." Dean slid off the bed, stretching his arms over his head before stumbling towards the bathroom. By the time he reached the door, he was walking straight, and he stopped before he stepped inside. "Hey, Sam? That Judas Priest hoodie of mine: did you take it to Stanford with you?"

Sam glanced up from his seat on the edge of the bed and frowned. "I was wearing it the day I left for Stanford. Remember? You were there at the bus stop with me?"

So it had taken. Good. "Yeah, sorry, I knew that," he bluffed, turning towards the bathroom with a smile. The world hadn't ended, and maybe...maybe the years at Stanford hadn't been too bad for either of them.

"Sure you did." Dean almost had the door shut when Sam added softly, "I was proud of you too, you know."

He paused and glanced back out into the room. Sam was smiling at him, a knowing smile. "Next time, though, let's decide what we're gonna go back in time for together, okay?"

Dean stared at him, shocked into silence for a brief moment, before the corners of his lips turned up. "I thought we did," he said as casually as he could before he closed the bathroom door.

He still caught Sam's smile broadening, gratitude and love obvious on his face, before he shut the door.