Because betrayal is betrayal wherever you find it
The letter is smaller than he'd expected, lighter.
Nothing to suggest its importance save the Standford emblem (so familiar to Sam from the prospectus hidden under his mattress, the many application forms filled out furtively in school libraries). Dark lines against white paper standing out like a brand.
Sam stares at the letter for exactly eight minutes before he can bring himself to open it.
He doesn't really read it, that first time. Just scans the rows of black lines, sees the words delighted and welcome and scholarship laid out like escape routes and then he's folding the paper quickly, slipping it into his jeans pocket before Dean's footsteps can reach their bedroom door.
Deception is a brutal thing. But Sam's carried a knife since he was ten, knows all the things that lurk in the dark ready to tear flesh and choke the life from the unsuspecting, has helped kill many of them. If deception is the price he has to pay for freedom Sam comforts himself with the knowledge it's his father's doing not his.
It's a brutal world and he's been trained for survival.
---
He carries the letter around with him for weeks after, a secret burning thing, hot against his thigh.
His father notices his additional distraction, this new kind of apathy and if it weren't for the acceptance letter safe and hidden in his pocket, the key to a better life, Sam would think nothing could escape the sharply knowing eye of John Winchester.
Even Dean can't protect him from the increasingly harsh comments and extra training sessions his father throws his way. "Gotta shape up Sammy" has become John's new mantra and Sam doesn't care.
He wears his resolve like armour. Keeps his head down as he runs laps, eyes on the ground and imagines himself already free.
---
If eighteen years on the road have taught Sam anything it's this: how to pack up and walk away without looking back.
Leaving is a simple matter of packing up the few things he owns (three hand-me-down shirts, one pair of faded jeans slightly too small, all the cash he possess and books, always books because they've been his way out of this life for as long as he can remember ) into the patched green duffle bag he's had since he was nine, and keeping his back straight, his hands steady as his father tells him in a soft voice that's gone beyond anger "you leave now you better stay gone".
Dean stays quiet, stays put, doesn't meet his eyes and Sam doesn't say goodbye.
Leaving is opening the faded brown door of the last motel room they'll ever share together and letting it shut quietly behind him.
Sam thinks it should be harder to abandon the people that love you.
---
Those first few months at Stanford are fear and relief in equal measure.
A normal life has been all he's wanted for so long and suddenly he's there learning how to live it.
Walking to the library, grabbing lunch with friends he revels in the knowledge that he can do this. Can slot himself into this life like he belongs there.
The first time he takes Jess out on a date he looks at her from across a table at her favourite Italian restaurant, her gold hair curling at the tips, lips red from the wine and he can see it all; a home, a family, a white picket fence, all laid out for the taking and if there are some things he's had to give up for this to be possible Sam thinks' surely it's worth it.
But sometimes, on a bad day, he wakes to the heavy silence of an empty dorm room and feels his brother's loss like a solid thing. Not so much an elephant in the room as a dragon, complete with sharp talons and fiery breath to slash and burn.
For eighteen years he never spent a night alone, the sound of Dean's breathing across the room a reassurance he hadn't known he needed until it was gone, and without it a feeling very close to desperation rises up to choke him. On bad days it takes every last inch of Winchester stubborness to stop himself reaching for the phone.
It's a new life, his new life.
Sam tries hard not to think about the cost.
---
After dorms comes an apartment and Sam no longer wakes up alone.
For a while he gets to wake to rain and the morning paper and the warm presence of Jess sleeping next to him.
He gets a house with freshly baked cookies and photographs taped to the fridge and all the possibilities of a life ready to be lived, stretching out before him like the open road his brother loved so much.
He clings to the normalcy of this life, wraps it around him like a blanket and tries so desperately to believe it will last.
And then, as suddenly as it comes, every part of his happy normal life goes up in flames and even as Dean's dragging him from the house, hands tight and familiar around him, he thinks he should have known better.
---
Six months on the road and the exact details of his life in Stanford begin to fade. He can't remember the timetable for his lectures or the name of the red haired lady who lived next door.
Twelve months and it begins to feel like a very vivid dream.
By eighteen months Sam has forgotten the shape of Jessica's eyes, the precise curve of her mouth as she teased him. He loses the rhythm of her laugh, finds it replaced with the deep stuttering sound of his brother's snores and the warmth of his easy, lazy smile.
Sometimes it's hard for Sam to look at his brother. He sees the extent of his own selfishness in Dean's unfamiliar scars, in his eager smiles despite Sam's desertion. In his ever present willingness to throw himself between Sam and anything that might cause him harm.
In the leather cord around his neck, that Sam knows despite four years of anger and resentment Dean has never ever taken off.
---
The burning need to avenge Jess' death festers.
It grows in him with every fresh wrong he witnesses, every new fact he learns about the yellow eyed demon until eventually it obscures the girl herself, the lost possibility of the life he could have had sharper in his mind than the reality.
Revenge spreads in him until it beings to eclipse everything else and Sam thinks he finally understands his father, thinks that for all their continued fighting they're finally on the same page.
That is until he sees his brother gutted on a grotty cabin floor, blood pooled like spilt milk. Until he hears him plead.
Sam knows he has a choice to make. He chooses Dean.
---
They failed. Finally succeeded in killing the latest in a never ending line of monsters but not before it killed three boys, children that died because of them, because they were too slow.
Afterwards, once they've showered and the weapons are clean and safely hidden away in the Impala's trunk they take shelter in the nearest diner. Neither of them is hungry but ordering food gives them something to do, something to fill the silence. The adrenaline hasn't quite worn off and Sam's hands still shake ever so slightly.
The Impala and the open road are waiting. Another job in another dead end town.
Sam looks at Dean, sitting opposite him, shabby and tired in his worn leather jacket, gloomily picking at his fries and cannot remember what it felt like to want anything else.
---
'There are different sorts of treachery but betrayal is betrayal wherever you find it'