Sam's approximately thirty-two hours old when Dean gets to hold him for the first time.

Mom and Dad bring him home from the hospital, all wrapped up in a white blanket like he's something really delicate that might shatter in a light breeze. Dean's scared; he wants to meet his new brother but he doesn't want to hurt him. He's so tiny, and Dean ruined a little paper swan Mom gave him last week because he squeezed it too hard. But Dad smiles and says it'll be okay, just that Dean has to be really careful.

They sit him on the couch, his socked feet just barely hanging over the edge of the cushion, and Mom slowly lowers the bundle of blankets down into Dean's lap. It's warmer than Dean was expecting, he can feel the heat from Sam's body through the blanket and his jeans. And when he leans over he can see Sam's little face; it's all wrinkly and red and funny looking, but then Sam opens his eyes and blinks up at Dean, and Dean's tummy does that funny, tickly feeling like when he was on the roller coaster at the fair last summer.

"Hold his head," she says softly as she arranges him.

"Why?" Dean asks.

"Because he can't hold it up by himself yet," she answers. "He's not strong enough. He needs his big brother to help him."

"Oh." Dean doesn't say it out loud, but he likes that. He likes the idea of Sam needing his help. "Okay. Don't worry, Sammy, I gotcha."

"You wanna call him Sammy?" Dad asks, and Dean nods.

"He looks like a Sammy."

"He definitely looks like a Sammy," Mom agrees, pulling her arms back and letting Dean hold Sam all by himself.

He stares down into Sam's eyes; they're kind of green like his but maybe a little blue like Mommy's. Sam blinks a few times, and then he yawns, and Dean giggles at his little pink mouth with no teeth in it. Then Sam wiggles his arm out of the cocoon of blankets and reaches up towards Dean with a hand so small Dean's heart starts thumping faster again. He doesn't want to touch it, he's afraid he'll break it and then Sammy will cry and Dean would probably cry too. But Mom nods at him and says, "It's okay, Dean. Just be careful."

Dean swallows and takes a deep breath, and then he reaches out and softly holds Sam's hand in his own. He concentrates hard on not squeezing it, just holding it gently like when he held Sarah Gobert's gerbil that time at her birthday party. Sam's tiny fist holds on to Dean's finger, and Dean's tummy flips again. He likes that too.

"Well? What do you think? Is he a keeper?" Dad asks.

Dean looks up at him and nods. "Yep. I like him."

Mom smiles and her eyes go a little shiny. Dad wraps his arm around her shoulders and pulls her in to lean against his chest. Dean understands why Mom sighs happily; it's really nice against Dad's chest. It's all warm and he feels safe there. He pulls Sammy in a little closer, wanting to make Sam feel just as warm and safe and loved as Dad makes him feel.

"He's mine, right?" Dean asks, repeating what Mom had said over and over before they left to go get Sam out of her tummy. "My little brother?"

"Of course," she answers. "But maybe you could share him with us?"

Dean thinks about it. He doesn't really want to, he wants Sam all for himself. But Mom always says sharing is good, so maybe that wouldn't be so bad. "Okay," he says reluctantly, "but I get him the most."

Sam's just a little bit older than one when he says his first word.

It's late, Dad's already asleep and Dean was too, but then he heard Sam crying so he got up to check on him. Sometimes Sam cries in the middle of the night and sometimes he doesn't – usually when he does, Dean hears Dad walk over and pick Sam up, his gruff voice floating through the air as he sings a lullaby that Dean recognizes as one Mom used to sing to him. But this time, he didn't. Dean listened to little Sammy cry for a long time, and no one was going to him, so Dean did it himself. He hates it when Sam cries, anyway. It makes him sadder than when his goldfish died. Sam's gotten bigger, but he's still so small and so helpless, all he can do is lie there all alone in his crib and cry until someone comes to him. It makes Dean's heart hurt.

So he gets out of bed and tiptoes across the room slowly so he doesn't wake Dad up. Sam's lying on his back, whimpering pitifully. Dean peers through the white bars of his crib; Sammy's face is all red from crying and there are wet spots under his eyes, but he quiets down just a little when he sees Dean.

"Hi Sammy," Dean whispers. "Why're you so sad?"

Sam's tiny brow furrows, and then he lets out another sob and Dean feels a funny, itchy feeling at the back of his throat.

"What's wrong?" he asks again, and this time Sam squirms around and points toward the floor near the drawers where Dad keeps their clothes. Dean frowns, and walks over to see what Sam's pointing at. He doesn't know, but then he gets down on the ground to check under the dresser in case there's a ghost down there or something, and he sees Sam's orange soother in the shadows. Sam must've dropped it; it must've bounced under the drawers.

"Don't worry Sammy, I'll get it," Dean says, but even if he lies flat on his stomach and stretches his arm as far as it'll go, he can't reach it. He gets up and tries to push the big dresser out of the way, he tries really hard but he can't move it. Dean sniffs a little and tries not to start crying himself. He really wanted to make Sam happy again and he doesn't like that he can't.

"M'sorry," he mumbles, walking back to Sam's crib and looking down at him miserably. "I can't reach it. I'm sorry, Sam."

Sam just looks at him, and there's something uncomfortable in Dean's chest that's making it hard for him to breathe, but then Sam reaches his little hand through the bars and touches Dean's arm. Dean smiles just a little – okay, if he can't get the soother, at least he can keep Sam safe until Dad can get it for him. He pulls the little step-stool Dad got him over and climbs into Sam's crib, careful not to land on Sam as he drops onto the mattress. Sam isn't crying anymore, but he doesn't look happy yet either, so Dean lies down beside him and rests his arm gently across Sam's round belly.

"I'll stay here with you, okay? Nuthin's gonna get you, not while I'm here," he promises, and Sam actually smiles.

"Dee," he says in a soft voice, and Dean almost jumps right out of his socks.

"You said my name!" he cries, forgetting for a moment that he's supposed to be quiet. "You said Dean! That's me, Sammy! I'm Dean, I'm your big brother Dean!"

"Dee," Sam agrees, yawning widely and snuggling into Dean's side.

"That's me," Dean says again, laying his head down and kissing Sam's forehead. "And you're Sammy. We're Sammy and Dean. Forever ever ever."

Sam's five when Dean walks him to school for his first day of kindergarten.

He's all ready. Dean taught him how to tie his shoelaces over the summer, and they went to a Walgreen's and picked out a backpack and some notebooks and erasers and pencils with Spiderman on them. Dean explained everything that was going to happen, that there'll be a teacher and lots of other kids Sam's age to play with, and at lunchtime Dad is going to pick him up and then Dean will be home at three-thirty and Sam can tell him all about what he did on his first day. But Sam doesn't want to go.

"What if the other kids don't like me? What if they're mean?" he worries.

Dad rolls his eyes and mutters that they don't have time for this, so Dean takes Sam by the hand and leads him to the bed. He sits down on the edge of the mattress and Sam sits beside him.

"They won't be mean, Sammy, I promise," he says rubbing Sam's shoulder reassuringly.

"But what if they are? What if they tease me or throw things at me?" Sam cries, slumping down against Dean's side and burying his face in Dean's neck. "Don't wanna go, Dean. Wanna stay with you."

"I know, shh," Dean soothes, wrapping his arms around Sam's trembling shoulders. "It's only for a little while. And then I'll be home later and we can play cops and robbers at the park."

Sam sniffles wetly, and Dean squeezes him a little tighter.

"Dean," Dad warns, tapping his watch, but Dean shoots him a pleading look so he sighs and plops himself down on the other bed. It's alright, it isn't Dad's fault. Sam is really sensitive; Dad just doesn't understand that. And he's little, he's only five. Sometimes Dean thinks Dad forgets that.

"You gotta trust me. And you gotta be brave, okay? Can you do that for me, Sammy?"

Sam heaves a sigh that wracks his small body in a deep shudder, but then he lifts his head up and there's reluctant determination in his watery hazel eyes. "Okay. I can try."

Sam's nine-and-a-half when Dean sees him win his first fight.

He's not supposed to be there, it just happened by co-incidence that Dean was walking back from the bathroom when he turns a corner and spots Sam down the hall, with two bigger and older looking boys flanked on either side of him. For a second, Dean thinks they're just talking, and he's a little proud of Sam for being cool enough to skip class. Sam's such a nerd, Dean never thought he'd see the day when Sam would play hooky voluntarily. But then one of the boys shoves Sam into the lockers, hard, and Dean realizes what's going on.

His first instinct is to sprint over there and lay the asshole out before he even sees it coming. Hot rage boils in his veins and he wants to make the guy pay in bruises for laying a hand on Dean's little brother, maybe even break his nose if he could manage it – and he could manage it, he's known how to break a nose since he was seven – but then Sam gets up so Dean thinks maybe he isn't hurt. He wants to protect Sam more than anything, but he doesn't want people to think Sam can't stand up for himself. They'd tease him if they thought his brother always had to be fighting his battles for him. Dean learned that lesson the hard way last year; Sam's small for his age and he's gentle in nature so he seems to be an easy target for bullies, and sometimes Dean can't help himself.

In his head, he's silently willing Sam to fight back so he doesn't have to step in, but Sam slouches in on himself and lets the other one shove him back down. They're saying something to him, Dean can't hear specific words but their tones are mocking and Dean sees red. He's about half a second away from charging over there and showing those two what happens when they mess with a Winchester, but then Sam gets up and out of nowhere, he slams the heel of his palm into the bottom of the bigger one's nose, just like Dean taught him. The kid cries out in pain, and the other one scowls and lunges for Sam, but Sam dodges out of his way. He grabs the kid's arm and twists it behind his back, getting a good grip on him and then pushing him toward the garbage can so he trips over it and lands in a heap on the floor.

Dean's in shock. He's never seen Sam do anything like that before. And then, he's so proud of his brother he's practically bursting. Sam straightens himself out and picks his backpack up off the floor, and Dean should stay hidden but he can't. He calls Sam's name and jogs down the length of the hallway to meet him.

"Dude!" he cries. "That was awesome!"

Sam's eyes go wide and his face pales at the sight of Dean. "You … you saw that? You're not gonna tell Dad, are you? Please, Dean, he's gonna be so mad at me!"

"What? No, I'm not gonna tell Dad," Dean assures. "Seriously, Sam, that was kick-ass. Those guys are twice your size and you just took them down!"

Slowly, Sam seems to realize that Dean is impressed, not mad, and a tentative smile breaks out on his face. "Yeah?"

"Yeah," Dean answers, throwing an arm over Sam's shoulder. "Remind me not to piss you off. You're lethal, man."

Sam laughs quietly, smiling so wide his dimples are carved into his cheeks like craters. His whole face lights up whenever he thinks he's done something to make Dean happy or proud – Dean loves it. He loves the way Sam looks at him, like he's the only person in the world who matters.

"C'mon," Dean says. "Screw math class, we're going for ice cream."

They walk away with Sam still tucked up against Dean's side, and if Dean happens to accidentally step on one of the kid's hands as he passes him, well, the guy deserved it.

Sam's twelve the first time a girl asks him to go to a school dance with her.

He's equal parts excited and nervous about it. The day it happened, he burst through the door all flushed and worked up and babbled fervently about it for almost twenty minutes, telling Dean exactly how it happened and where it happened and every word that she said. But then the day of the actual dance, Sam's anxious and pale and he doesn't seem to think it's such a good idea anymore. He grills Dean relentlessly about what he should wear and what he should do, if he should tell her she's pretty, how boys and girls are supposed to dance together, what to do if he steps on her feet, if he should kiss her. Dean answers each question patently, because that's what big brothers do, but by the time Sam's dressed and primped and out the door, Dean has a funny, tight feeling in his chest he's never felt before.

He doesn't know what it is, but he's sure he doesn't like it.

Sam's a few months away from turning fifteen when Dean first realizes it's his little brother he's been picturing when he's with a girl or touching himself in the shower.

Rhonda Hurley is the hottest girl Dean's ever been with by far. She's unbelievable, she belongs in magazines or on a TV show or something. She has these long, dark curls that Dean's just dying to get his fingers in; lusciously plump lips that make his mouth water when he imagines them wrapped around his cock; and smooth, ivory skin that just begs for his tongue to taste every inch of it. She's older, almost twenty-two, and Dean should consider himself lucky she's even giving him the time of day. His night with her is amazing; she's not shy and embarrassed and tentative like girls Dean's own age are. She knows what she's doing and she does it well. She pushes him against the wall, grinding her hip into his crotch while she kisses him. She sucks his cock like she's trying to win a prize. She makes him try on her pink panties, and as potentially humiliating as that is, it's kinky and kind of dirty and Dean likes it. And then she rides him like a mechanical bull, bouncing and rolling on his rock-hard dick until he sees stars.

It's what he doesn't see, though, that's much more troubling. Her. When he closes his eyes and lets his orgasm wash over him, it isn't her face he sees on the inside on his eyelids. She's the opposite of Sam in every way; she has black hair instead of golden-brown, bright blue eyes instead of hazel-green, porcelain skin instead of caramel, and she's short and curvy where he's tall and lean. So really, there's no logical explanation as to why Dean's brain got confused and imagined a shaggy mop of hair and soulful eyes and to-die-for dimples while he filled up the condom and Rhonda squealed on top of him. And the worst part is, once the realization hits him, it suddenly becomes clear that this isn't the first time this has happened.

For a long time, Dean's really unhappy. He's upset and scared and confused and disgusted and he hates himself for having all these feelings, and it all adds up to almost a year of pure misery. He pulls away from Sam, physically and emotionally – which of course Sam notices right away because the kid is crazy perceptive – but Dean won't talk about it, can't talk about it, so Sam spends the better part of the year miserable too. It's a horrible situation any way Dean looks at it. He doesn't want to be distant with Sam, he wants the exact opposite actually, but that's the problem. And he has no idea what else to do. He's so terrified that if he lets himself touch Sam, he won't be able to stop. Dean may be sick right down to his core, but he's not about to drag Sam down with him.

Sammy is still good and sweet and innocent – Sammy still has a chance to escape this black web of revenge and hate and violence that Dad and Dean have spun for themselves. Adding recently acquired incestuous fantasies to the mix, and Dean's almost shocked Sam's managed to turn out mostly normal after growing up the way they did. Sam's the one ray of light in Dean's life. No way in hell is he going to be the one to ruin that.

Sam is sweet sixteen and beautiful when he sucks Dean's cock for the first time.

He's nervous, Dean could've spotted it from a mile away, and he keeps insisting that Sam doesn't have to do this, but Sam seems stubbornly set on giving it a try. He's worried it won't be good; he's never done it before and Dean's been with lots of chicks who had done it before, so Sam's afraid he won't measure up. Dean tells him that's ridiculous, he promises over and over that whatever Sam does will be amazing because it's them, so automatically it's better than anyone else. Sam doesn't look entirely convinced, but he's nothing if not determined, so he slides Dean's boxers down enough to tuck under the swell of his balls and takes Dean's hard cock in his hand. He strokes it a few times gently, nothing he hasn't done before, and then he tentatively sticks his tongue out and licks at the head.

Dean was definitely right about it being good based solely on the fact that it's Sam doing it. Sam doesn't have much technique at first, but he's enthusiastic enough that it more than makes up for the way he sort of fumbles through it. Dean tries to moan obviously when Sam does something that feels good, and Sam catches the not-so-subtle hints and picks the skill up in no time. His mouth is hot and wet and perfect, and it's so forbidden and dangerous and just plain wrong that Dean's dick is on his baby brother's tongue that he's thrown over the edge embarrassingly quickly. Sam doesn't swallow Dean's release, Dean wasn't expecting him to, but he does lick it off his fingers afterwards and the sight alone has Dean ready to go for round two faster than ever before.

He hauls Sam up the bed and kisses him thoroughly, groaning at the slightly bitter taste of himself masking the usually honeyed taste of Sam's sweet mouth. Sam kisses back, tongues and lips and teeth battling together until they're breathless, and then Sam pulls back to gasp for air and glances up at Dean with a shy smile.

"Was it okay?" he asks softly.

"Okay?" Dean repeats incredulously. "It was fantastic!"

"Really?"

He looks so hesitant and hopeful that Dean has to kiss him again; sliding his arms around Sam's waist as he does and holding him close.

"Fuckin' amazing, baby boy," he whispers against Sam's kiss-slick lips.

Sam's eighteen and just on the cusp of adulthood when Dean loses him, and he's twenty-two and somehow halfway between impressively masculine and still ridiculously adorable when Dean gets him back.

The time in between, he doesn't like to think about. It hurts too much. Sam was gone for a really long time, but he's back so it doesn't matter anyway. There are miles and years and heartbreaks between them, but Dean has his Sammy back, so he barely has the inclination to care about all those things that are in their past now. Sam's more than Dean's brother – he's his best friend and his hunting partner and his everything else. The death of Sam's girlfriend mars their reunion initially, but it isn't long before they fall back into perfect sync with each other like they were before. They hunt like a well-oiled machine; they laugh and joke and poke fun at each other; they fight to the point of tears or one of them storming out, but then they make up with kisses and sweaty bodies and fingers squeezing bruises into hipbones.

It's imperfect perfection, and Dean almost stops caring if they ever find Dad. He'd happily live this way forever – just him, Sam, his baby, and the open road.

Sam's twenty-three when Dean loses him for real, not just to school or a girl or dreams of normal.

He makes the deal because he has to. It's Sam, and Dean's purpose in life is to keep Sammy safe. It couldn't be more embedded in him if it was carved on his bones. Sam was dead, actually dead, and Dean had a way to make it better, so he did it. Hell is one thing, but living in a world without Sam in it is not an option. Case closed, end of story.

Sam's twenty-five, and barely a hollow shell of the amazing person he used to be, when an outside force comes between them for the first time.

Of course, there've been interlopers before; they've known each other for over two decades, it would be impossible for their relationship to have been consistently rock solid for all that time. But Ruby is a different kind of cocktail entirely. Dean hates her, he hates every single thing about her. She's like a cockroach that he wants nothing more than to squash with the toe of his boot. He hates her obnoxious and condescending demeanor, he hates her irritating voice, he hates her black leather jacket, he hates her stupid, froggy face, and he hates that she has Sam wrapped around her little finger.

She was around before he went to Hell, too, but back then she was blond and fiery and at least kind of cool and badass, in her own way. She gave them the demon-killing knife, after all, and she helped Bobby fix the Colt. But now she's just a toxin. Dean doesn't know exactly what went on while he was down under, but evidently she spent the entire time – four months, Sam says, although it felt a lot god damn longer where Dean was – whispering in Sam's ear and lying to him and manipulating him and taking advantage of his grief-stricken state. Before Dean even got back Sam was probably too far gone to help, but then Dean's so consumed with his own broken psyche that he doesn't notice how far Sam's slipping until it's much too late.

Sam starts the Apocalypse, with a lot of help from a malignant demon bitch that Dean's more than ecstatic to drive a knife through. They'll find a way to stop it, probably, but it changes them nonetheless. Dean makes excuses, but it isn't the blood or the lies or the betrayal. It's that Sam's different. When Dean was little, Dad put him eternally in charge of taking care of Sammy, and somewhere along the way, Dean slipped up. He wasn't looking closely enough, or listening hard enough, or paying enough attention. Somewhere along the way, Sam went left when Dean should have been there to tell him to go right. He's different, and Dean's mostly given up hope that he'll ever truly get Sammy back. If he ever had him back in the first place, which at this point is, unfortunately, debatable.

Sam's twenty-eight and somewhat akin to a shattered vase held together with scotch-tape when Dean finally, for the first time in way longer than he cares to think about, feels like him and Sam are back where they're supposed to be.

The Apocalypse came and saw but didn't conquer, thanks to Sam, and then he was gone and Dean was alone, and then he was back as a terrible, animatronic version of himself and Dean was even more alone. And then he was put back together and smashed to pieces so many times Dean lost count. Dean's broken right along with him. He feels every brick that falls as the Great Wall of Sam slowly crumbles, and he feels it like a white-hot knife to the gut every time Sam twitches and goes wide-eyed and scared and Dean just knows his poor, damaged little brother is seeing Lucifer in some dark corner of whatever room they happen to be in at the time. He wishes more than anything that he could take all the pain and the fear and the cancerous memories away from Sam; put them on himself so Sam doesn't have to suffer anymore. But he can't.

Eventually, though, Sam starts getting better. It's slow, but Dean can see it happening, step by step. He screams in his sleep less, and the hallucinations start to taper off, the space between them getting longer all the time. Sometimes Dean still catches him staring into space and digging his thumb into the scar on his palm, but even still it seems to be getting better. Brick by brick, Sam's piecing himself back together and every day he seems more and more like the sweet, sensitive, wonderful little brother Dean used to know. They've lost so much, Mom, Dad, Ash, Ellen, Jo, Pamela, Rufus, and most recently, Cas. That one hurt Dean more than he'd ever be able to say. Cas was more than his friend; he was Dean's ally in a world that seemed hell-bent on breaking him down, and it still makes Dean's chest ache to remember that he's not with them anymore. But through all the tragedy, he still has Sam, and on his better days, Dean's not sure he could ask for more then that.

"So you think it's a spirit?" he asks, glancing over at Sam from across the Impala's bench seat.

"Yeah," Sam answers. "I mean, it could be something else I guess, but the way this thing moves, man, if it can't go through walls it'd have to be crazy fast."

"Okay. Well, we'll EMF the place, see if we can pick anything up."

"Sounds good. Who are we this time? FBI?"

"That's probably our best bet," Dean muses. "People don't usually question feds."

Sam nods, and then he goes quiet and stares out the window for a minute.

"Hey, um …" Dean starts slowly. "Are we okay?"

Sam frowns. "Yeah, 'course we are. Why, what's up?"

Dean shrugs. "Just checkin'."

"Oh. Well, yeah, we're good. It's you and me, right? We're Sam and Dean. That's forever," Sam says, only half-joking and oddly reminiscent of what Dean said the first time Sam said his name. Funny thing is, Dean's never told him that story.

He smiles to himself, and then to Sam, shaking his head and laughing a little. "You're such a girl."

"But you love me," Sam returns, sticking his tongue out at Dean, and Dean laughs in spite of himself.

"Yeah," he agrees. "I do."