A/N: Because I can.
Oneshot.
Don't own Supernatural.

"The reverse side also has a reverse side."

-Japanese proverb.

Sam doesn't knock, though he tries out of politeness more than anything. The door flies open before he has to, so he's left with his fist hanging in the air uselessly as his brother stares at him with an intensity he hasn't seen in a long time. He's missed it, like he missed his big brother four years ago, but he's not going to admit it, not now, not ever.

"Sammy," Dean breathes, and reaches out to grab his shoulder, his neck, his hair, whatever. Sam moves back, partly out of instinct but mostly out of spite. Dean doesn't seem to take it too personally, and just lets his arm fall back down as his face splits out into a large smile. "Sammy!"

"Dean," Sam says, curtly, and tries to stay neutral, to pretend there is no emotion in the world and that the person he's talking to isn't his role-model of a big brother who ditched them for higher education four years ago. Four years ago, when Sam needed his brother most. Four years ago, when Dean decided life would be better without a little brother holding him back.

Dean looks well. Hair is messy and a little longer than Sam remembers ever seeing, but there aren't any lines of worry and stress that mark his face like Sam does remember seeing, growing up and counting them, watching them represent everything Sam hated about life as a hunter. His eyes are light, a bright green that said I'm happy in a way that it never really did when they were with Dad.

Sam is suddenly seized by the same feeling that had been pestering him for hours now, and very nearly listens to it, turning on his heel and just walking away, but Dean's arms suddenly wrap around him, a hug, in a break-your-ribs-painful kind of way, for all the wrong reasons. Sam freezes, and Dean manages to turn Sam around so they could speak, argue, scream, face to face.

"Sammy," Dean says again, voice happy but tight, because Dean was many things - jerk, asshole, big brother, deserter, charmer, deadbeat - but stupid was never one of them. He didn't expect his puppy-eyed little brother to show up on his door step because he wanted to see him, to say hi, to chat and have coffee. Sam always had the higher IQ level, but Dean was the one with better intuition. "What's up?"

Sam shoulders his way inside, roughly past Dean, and Dean lets him. His brother's apartment is an odd balance of messy and neat; there are papers in a jumbled mess on the kitchen table and a tiny desk crammed into the corner, but the stove and and sink are spotless and empty, and there aren't dirty clothes littering the floor like Sam would have expected. He lost track of how many times Dean would just dump his jacket on the floor whenever he got back from school or an errand, back when they were kids and brothers and a family.

Dean closes the door and, almost absent mindedly, clears a spot at the table for him and fetches coffee, like Sam was just any other late night visitor he wasn't quite prepared for. Sam doesn't touch the plastic cup that is set down in front of him, but doesn't look his brother in his too-green eyes either.

"Sammy," Dean tries, uneasy, and Sam cuts him off before he can proceed.

"Sam." He corrects. "Just Sam."

Dean blinks, like the subtraction of 'my' from 'Sammy' is a completely foreign threat he doesn't know how to handle. Sam offers no smile or sympathy, no jokes, nothing Dean can play off of. So Dean does what he's always done and just push past what he doesn't have time to deal with and leave it behind.

"Sam, then," Dean says with a hint of exasperation and a ton of annoyance. "What the hell are you doing here, man? Is everything alright?"

"Everything is as it's always been," Sam replies. "Not that you'd know."

A beat. Dean doesn't look surprised, but he does look hurt. He's biting back a harsh reply, a vulgar insult on the tip of his tongue, but Dean has gained restraint in his time in college. Sam can't bring himself to not both hate and respect him for it. Dean grew up a little, finally, and wasn't even around to show it to the people who should have mattered most.

"Then what's up? You're not going to tell me you came all the way up to Massachusetts just because you like the north."

"I'm here because..." Shit, this was a lot easier when he envisioned it in his head. Words, they're just works, followed by actions and then a resolution. He can deal. He will deal. "Because I need your help."

Dean doesn't hesitate. Doesn't say, "No, you don't.", or "You can do this without me."

"What do you need?" There's a little earnest spark in his voice, more than a hint of hope.

Guilt, Sam sees.

Too little, too late, Sam thinks.

"Dad's missing." He says anyway, because family looks out for each other, and Dean is the one he always told him that. "I need you to help me find him."

Dean, apparently, has the weekend off, so he can go state-touring with Sam until come Monday morning, when he's got some important class for his future career. Dean seems confident that they'll find Dad before three days is up, and isn't too convinced that he'll miss his tests. Heaven forbid something come before that, Sam thinks, but doesn't say. He doesn't say a whole lot these days. Hasn't for a couple years.

Sam shows Dean all the evidence he's got, the last messages John Winchester left behind, and gives a few theories in a voice flatter than day old soda. Dean is rusty, and it shows, but he's always been fast at picking things up, and hunting is a lot like riding a bike. It just takes a little time to get back into the swing of things, and he's relatively decent at his job again.

"Haven't had a case in two years," Dean says to the air, because Sam hasn't responded to anything not pertinent to finding Dad, and his brother probably keeps talking just to fill the silence. His voice is mixture of nostalgia, excitement, and worry he tries to mask, worry for a father he abandoned, so Sam doesn't offer comfort nor sympathy. "Last time I did anything hunter related was just a simple ghost, haunting this chick that accidentally hit him in a car crash a little ways off from school campus. Easy, quick, and a helluva lot weirder alone."

Alone. Sam's been alone for a lot longer than that, since Dean left, since Dad left. Dean's departure had been sudden and shocking, the loyal soldier deserting his unit in the middle of a war, of a mission. Dad didn't speak to Sam for months. No one mentioned Dean in any way, shape, or form for nearly a year. Dad's departure was almost welcome; between their screaming matches and fights, they got almost nothing done and separating was painful, not as much as Dean's, but the hurt was far outweighed by the benefits, even if loneliness stings at Sam every night and day.

One thing that Sam and John could always agree on, though, was that Dean was a sore subject not to be discussed. John resented his eldest son leaving them and their cause. Sam resented being left behind. He had dreams, he wanted to be something more than a hunter. He was good at it, yes, but never good enough, not like Dean. Didn't like it like Dean did. So it angered Sam as much as it puzzled him that Dean threw that away to become a forensic anthropologist. A ridiculous career in science. Dean never even liked science much in High School before he dropped out. How Dean managed to get into such a good school with a full ride, armed with only a GED had been a mystery Sam has spent hours not pondering. Because Dean was everything until he left.

Then he became nothing.

At least. He should have.

When they find Dad's room at the motel, it's plastered with papers and thoughts. Lots of dedication for anything that was yellow-eyed demon related. Sam leafs through them while Dean investigates the rotting food.

"Dad figured it out," Sam informs Dean, pulling the picture of it's legend off the wall. "Woman in White."

"'Course he did." Dean replies. "But then why the hell isn't he here?"

Sam has no answer.

Finding out the whos and whys are easier than usual - one guy asking around town is suspicious, and usually, two people doubly so. But Dean's charm coupled with Sam's sad eyes seem an extremely potent combination not many are immune to. They talk to the Woman in White's still living, ever regretful, very pissed off husband, question the sad, lonely, girlfriend-of-the-actually-unfaithful-boyfriend-who-recently-died Amy, they get rid of the spirit plaguing the Centennial Highway, and manage to not get arrested while doing so.

"We make a great team, Sammy." Dean tells him, as he swings back into the driver's seat of his not-Chevy Impala '67.

"It's Sam," He correct automatically, and tries to ignore the pain that comes with that statement.

They do make a great team. Hunter's often work alone, but in pairs, tend to be more effective. Divide the work, watch each other's backs, and keeping themselves sane. Sam's gotten used to the extra work that comes with being alone, the extra stress that threatens to consume him. But being with Dean... Dean's stupid car that is nothing like the Impala he left them with, Dean's stupid habits Sam had never forgotten like taking the bed closest to the door or always taking the first bite of a candy bar with the right side of his mouth, Dean's laughter, Dean's annoying jokes and numerous pop culture references, Dean's face when he got annoyed...

It felt nice.

It felt like home.

It felt too good to be true.

And it was. Because Dean was going to go back to school on Monday, and leave him alone. Just like everyone else in his life has.

They split up somewhere in Boston, early Monday morning, near Dean's apartment. There are no goodbyes, no chick flick moments, not even a wave. Dean walks, and doesn't look back. Sam tries not to feel disappointed.

Sam slides into his car, some truck Dad left him with when he took the Impala and went wherever that fateful day a couple years ago. It's large, but efficient and clean. Hard to sleep in due to his height, but he's done it when the occasion arouse.

He starts the engine, and is reluctant to shift it into reverse and just leave, like he should. They didn't talk about why Dean left, or what Sam thought about it, or forgiveness and guilt. Anytime Dean saw something that could head into potential soap opera territory, he shut it down. Whenever a discussion breached a topic Sam didn't want to touch, a distraction was made and Dean usually went for it, because Sam would ask him to, and Dean never said no to anything he asked.

If Sam asked, Dean might even leave his future behind, college life, friends he's made, everything, and come back. Be his big brother again.

But Sam can't.

Can't ask him to, just like he couldn't when Dean told him he was leaving, that enough was enough, that mom wouldn't have wanted this, Sammy! He's seen how much healthier Dean looks, without hunting, without a little brother and father holding him back. How much happier Dean has been, a sheer contentedness Sam has never seen in a regular person, much less his brother.

Sam hates being alone, hates his brother for leaving, hates his life because he hates hunting.

But he still loves his brother above all else, and would die for him.

So he will. He'll die young, probably hunting something or getting into a tragic car accident or something, to ensure Dean's happiness.

Sam nearly jumps when the passenger door opens and a duffle-bag flies into his face.

"Are you going to sit there dreaming all day, Sammy? Or are we gonna get movin'?"

Reality is unrealistic, Sam thinks, as he shoves the bag aside and watches his older brother pull himself up and into the truck, slamming the door behind him.

"Dean?" Sam asks intelligently, because thinking is a bit of an issue right now, foggy like a magic eight ball, try again later. "You. I. What?"

"Let's go already," Dean stuffs his bag underneath the dashboard, making a ton of unnecessary noise while he's at it. "I don't want to get stuck in traffic - do you know how much of a pain in the ass that is? It's not a wonder why the hell we always stuck to small towns growin' up. Too many damn people in big ass cities."

"What are - what are you doing here, Dean? We've finished the case - don't you - you have class and tests and - "

"Dad's not found yet," Dean says simply. "I promised I'd help you find him, and when have I ever broken a promise to you? ...Minus that one."

That one.

I'll never leave, Sammy. I promise, okay? Now shut up and go to sleep.

The car suddenly plunges into silence and tension.

Dean only broke one promise in his life, the most important one. Sam didn't forgive him for four, long years. He'd been sixteen, and his world had lost a huge continent when twenty year-old Dean Winchester left the planet for a entirely new universe, and Sam couldn't forgive him for it. Dean left. No word of warning. No signs of the incoming collision that was Dad, I'm leaving for college tomorrow morning.

"Why," Sam's voice is soft, too soft, and Dean tenses at the question he knows he doesn't want to answer. "Why, Dean?"

"Because." Dean's voice is clipped, pitched down, and at a volume that makes it so hard to hear. "I left for you."

Because that made a whole lot of sense.

"...What?"

"You had hopes and dreams. I... didn't. I wanted to be a hunter, Sammy, I really did. But you didn't. And if Dad had his way, you weren't going to have a choice in the matter." Dean shifts, and looks truly uncomfortable. "Set an example, make an escape hatch, do what had to be done. I figured, if I left, then you could too. Dad is a marine, a hard-ass, but he was a father sometimes too, and every parent loses their kid to college eventually, right? So have him hate me, instead of you, and get used to the idea of letting us go, y'know? I thought... I thought this was along the lines of what would happen, what you wanted."

Sam has no answer.

"I'm... sorry, Sammy. I should've told you, I really should. And I should have come back for you, or at least waited until you were eighteen or somethin'. But I couldn't take you with, the scholarship had a pretty tight deadline, and I never thought..." Dean clears his throat, just as Sam's starts to constrict. "Dad was supposed to let go, not hold on tighter. Should've known though, right? I mean, our whole childhood was shaped the way it was 'cause of the demon that killed mom."

"Dean..."

"So I was stupid, and went with a plan that I should have told my smarter little brother about, and I know I hurt you and Dad." Dean looks over at him, first time since the conversation began, and eye contact is made and Sam holds it as steady as he can. "And I'm sorry. I can't take back the years, or the pain. But I can come with you, and do what I do best."

"And that is?"

"Be your big brother." Dean says, like it's the easiest question in the world. And it is.

Sam smiles for the first time in years.

"Besides," Dean tells him, "I never even liked science much anyway."

Fin.