When Dean Winchester is four years old, he carries his brother out of a burning house. It sets a precedent, although he doesn't realise this until years later. Take your brother and run. Look after Sam. Always protect Sammy. He stands on the lawn with Sammy in his arms, and he wonders where his Mom is.
He understands death in a general sense, but this is the first time it's touched him personally. It's not until his fifth birthday a couple of months later that he finally gets it – she's never coming back. He cries on his bed for a while, and he lets himself think of his Mom. He's interrupted by a noise from Sam's crib. "Dean!"
It's his first word.
Dean's eight and a half, and he's in trouble. He sits on the hard wooden chair outside the principal's office, feet barely touching the floor. He doesn't know what he did wrong, but his teacher was really, really angry. He's not too worried about that, but he is scared of what his Dad's gonna say.
John sits his son down that night, and he tells him The Rules.
"Other people... they don't understand what I do, Dean. They don't know what's out there; they're lucky like that. So don't... don't bother arguing with people, trying to make them see sense. They won't listen – they don't want to know; they're happier being ignorant. Just... don't talk to anyone else about it. Okay?"
Dean nods, and says, "Yes, sir." He gets it now.
Dean's nearly fourteen, and he senses a change in the way people – especially women – treat him. He used to get patronising smiles and how can I help you, young man? Now, librarians and waitresses flutter their eyelashes and grin at him. They say if there's anything else I can do for you... anything at all, which makes Dean think of sex. Although that's not such a surprise, considering nearly everything makes him think of sex at the moment.
His brother still hero-worships him, and Dean's grateful for that. It's nice to know that in a life of duffel bags and motels, demons and ghosts, he has one constant.
Three weeks before he turns fifteen, Dean loses his virginity.
Her name's Sophia, and she's a senior in high school. He meets her at a party after his father – very grudgingly – gives him the night off babysitting duty. He's probably not supposed to be there, but he's tall and handsome and confident, and no one challenges him.
Sophia's an exchange student from Argentina. She has dark hair, dark eyes, dark skin, and a body formed from years of swimming and playing polo. She eyes him appreciatively almost as soon as he arrives, and he raises an eyebrow as he returns the look. After a few minutes of introductions and idle chitchat – during which Dean tells her he's seventeen – she hands him a beer and says, "Are you bored yet?"
The suggestive tone combined with the alcohol makes Dean confident, and he slips an arm around her waist. "The company's pretty good," he murmurs, and she laughs.
"What do you say we head upstairs then?" she whispers seductively, and Dean's more than happy to comply.
It doesn't last long, but Sophia seems to take that as a challenge, not an insult. Over the next two months or so, she teaches him all sorts of tricks with his hands, his tongue, his body. She goes back to Argentina in March. She doesn't ask Dean to write, and he doesn't offer.
Sam's a lot happier after she leaves, but Dean figures it's good for him to learn that he can't hang out with his kid brother all the time.
Dean's seventeen when he walks in on his brother masturbating.
He doesn't really know where to look, and Sam's blushing hard enough for Dean to know his blood flow's adjusted. He won't look Dean in the eye for a week, but then Dad takes them out training for a couple of days, and there's no more room for embarrassment.
Neither of them ever mentions it again, and Dean can never be sure whether the shirt Sam was holding belonged to him or not.
When he's eighteen, Dean hears an uncomfortable truth from a girl called Amanda. He doesn't really care that she feels sorry for him; he's turned that to his advantage before. No, what freaks him out is the way she says "the way you are with your brother." For a split second, Dean's heart turns cold as all sorts of unexpected notions click into place; but that's not what she meant, can't be what she meant, and surely thinking it reflects more on him than her. He snaps back at her, something about I'm a hero – he doesn't really want to dwell on it too much.
He's different around Sam after that. Still looks after him, still cares about him; but he doesn't wrestle with him the way he used to. He's afraid that now the idea's there, something will happen, and he won't be able to control it. Sam senses the change in dynamic, and he slowly starts to pull away from his older brother.
Dean's twenty when his brother kisses him.
They're fighting over something; something really stupid, like Sam not cleaning up the takeaway boxes. But they've been cooped up in a motel room for a few weeks, they haven't heard from Dad in four days, and their nerves are frayed. Dean throws a pizza box at his brother, who knocks it out of the way and steps toward him. At first he thinks Sam's going to hit him, and he's prepared for that. What he's not prepared for is Sam's hand grabbing the back of his neck, pulling him close, and mashing their lips together.
Somewhere in the back of Dean's brain, there's a little voice screaming this is wrong. He ignores it, and pulls his brother closer.
Dean's world falls apart when he's twenty two.
Sam gets offered a full ride to Stanford, and he's ecstatic. Dean's proud of him – of course he is – and he tries to hide his pain, his sense of betrayal. Sam, his Sammy, is just going to up and leave, and there's not a damn thing Dean can do to stop it. He stays out of the way as his father and brother scream at each other, and he drops Sam off at the bus stop the next morning. They kiss goodbye, and Sam promises to call.
Dean thinks it feels an awful lot like goodbye.
Dean's twenty four, and Sam's telling him not to call anymore.
"Her name's Jess," he's saying. "She's sweet, and funny, and she wants me to move in with her. Please, Dean, I just... I need this chance to be normal. Please."
Dean wants to rant and rage. He wants to break down. He wants to punch something. Instead, he just says, "Yeah, whatever, man. Have a nice life."
He thinks about trashing his cell, buying another one, but he doesn't. He tells himself it'd be an overreaction – but really, he's hoping Sam will change his mind.
When Dean's twenty six, his father disappears.
He's not too worried at first. Dad has a habit of getting drunk and forgetting where he put his phone, or his keys; he always turns up when he's sober again. But over the course of a week, annoyance gives way to worry, which in its turn gives way to panic. He's never been gone this long. He tries to find Dad himself, but he can't do it on his own. He doesn't see a lot of choice – he needs Sam.
He thinks about calling, but he knows Sam won't pick up. In the end, he bats his eyelashes at the woman in Stanford's student centre, tells her it's a family emergency, and she gives him Sam's address.
The first thing he thinks is how tall Sam's gotten; he didn't think his brother could grow any more. But all thoughts of his height are driven out when Sam lands on top of him; that brings back a whole lot of memories Dean's been burying in a bottle for the last couple of years. So maybe he's a little rough when he pushes Sam off, but that's only because his body remembers what his little brother can do.
He thinks it's a lost cause, at first. Sammy's all wrapped up in his cotton-candy safe life; no room for hunting. No room for his brother. But then the demon gets his girl, and suddenly Sam's filled with that thirst... that drive for revenge that seems to run in the Winchester blood.
Dean's so happy to have Sam back, he doesn't push for anything more. He just lets them be brothers.
Dean's twenty eight when Sam dies.
He makes a deal with the devil – literally – to save his brother. It's starting to become some kind of twisted family tradition, but when he's faced with it, Dean knows there's nothing he wouldn't do for Sammy.
When Sam finds out, he's furious. He yells, he punches walls, and then he's ominously silent. After a few hours of this, Dean snaps, pulls him close, and kisses him.
It's like the last four years never happened.
Dean's deal comes up when he's twenty nine.
Sam spends the year trying to find an out – even going so far as to offer himself up, the moron – but Dean's resigned. He's tired of hunting, tired of running. The only thing that makes it hard is Sam.
The hounds come for him, and he knows he should feel pain. But the hounds' claws, and teeth – they've got nothing on the look of despair on Sammy's face. That breaks his heart.
He spends forty years in Hell, by his reckoning; tortured, torturing. When Castiel lifts him out, he doesn't know whether he's happy or not.
But then he finds Sam. And once he's convinced his brother that it's really him, nothing else matters. Nothing.
When Dean's thirty, Sam breaks the final seal.
He'll never know whether Sam knew what he was doing; there was the demon blood, after all, and the look on his face as Lucifer rose... hell, it was equal parts amazement and fear. But Dean believes that his brother's still inherently good – he has to believe that, or he might go mad.
He forgives Sam. There's a war to fight, after all, and there's no one else Dean wants beside him.
The world ends, and Dean goes with it.
There's no Heaven, and no Hell; the war saw to that. There's just darkness, and empty space – and Sam. His brother is by his side, and that's all that matters; that's all that ever mattered to Dean.
The two of them are endless, and together. Always, together.