The thing Dean would always remember about Cold Oak, South Dakota, was the way Sam had looked at him right before he'd died.

His own relief, Dean could grapple with. He'd spent a good twenty-four hours not sure where his brother was, just knowing a demon, or demons, had taken him. That they'd been building up to it for a long time. He'd half-expected to find Sam in a psychic fit, or comatose out here alone. So when he saw Sam staggering toward him, gripping his shoulder, moving like he was hurt, but alive, Dean was relieved.

It was Sam's expression that killed him.

The way Sam's face split with a reassured smile, the overjoyed glint in his eyes. He'd looked at Dean the same way when he'd been a prisoner of man-eating hillbillies, and Dean had found him. That look asked him what had taken him so long, and told him that even that didn't matter, because he was here now.

"Dean." The way Sam said his name, he sounded like he was nine years old again, the same nine year old that had fallen asleep with his head on Dean's shoulder because he wasn't too old for a stupid story to help him sleep. The same nine year old that never heard Dean promise he'd take care of him.

For the first time in twenty-four hours, Dean felt the knot in his chest loosen.

That was when he saw the shape rising up behind Sam, moving too slow for a demon, too quick to be a normal human. Dean's finger curled on the trigger and stuck there, but his voice didn't; didn't stick, but burst out, all panic and anger and hatred:

"Sam, look out!"

And for one second, Sam looked confused. Just for a split second when their eyes met, Dean didn't see any reflex, any of Sam's training kicking through. Just pure, childlike, innocent confusion that didn't understand why the nightmare wasn't over yet. Didn't understand why Dean was standing frozen before him, face in a rictus of shock and fear and agony. Didn't understand why his big brother looked like he was shattering,

And then the pain of a knife sliding into Sam's back scissored through that confusion, and broke something inside of Dean that unlocked his muscles and started him running, screaming, "No!" like he could somehow change what had already been done.

Sam fell to his knees, head thrown back, the stars reflecting in his eyes for a brief second before they closed. Dean knew that look of pain, he'd seen it a hundred times on Sam's face growing up. He knew the huffs of his brother's breaths, chilling, slowing out. It was a sound that exceeded every other pain—and then it numbed. Numbed like that pain wasn't supposed to as Dean tumbled to his knees and grabbed Sam's jacket, pulling him down, settling him in a gentle grip.

"Sam, Sam. Sam. Hey, hey…c'mere, c'mere, let me look at you." Dean propped Sam against his chest, one arm keeping him safe and steady, and reached for the wound, to stop the blood and pain with his own hands. They came away from the jacket soaked in scarlet, the kind that Dean knew, he knew it wasn't—

He closed his eyes for one second, just pushed it away, and sat Sam up again. "Oh, hey, look. Hey! Look at me. It's not even that bad. It's not even that bad, all right?" Sam's gaze slid sideways, hope dying in his eyes, like he was realizing Dean couldn't do this, he couldn't—blood was pooling at the corners of Sam's mouth. "Sammy? Sam! Hey, listen to me, we're gonna patch you up, you'll be as good as new, huh?" Sam's head lolled, chin resting on Dean's wrist. Dean reached for Sam's face, steadied his head between his hands. "I'm gonna take care of you, I'm gonna take care of you. I gotcha. It's my job, right? Watch out for my pain in the ass little brother." Dean tried to smile, tried to make this funny, make it something they could laugh about in a few hours when Sam was stiff and sore and getting better and—

And he couldn't laugh this one off.

Sam wasn't looking at him anymore.

"Sam? Sam." He brushed the dark, sweat-matted hair off his brother's forehead, shifted Sam's face in his hands. "Sam." Sam didn't move, he looked like he was asleep—not peaceful or in pain, just asleep. "Sammy!"

Eyes closed, Sam slumped in Dean's grip.

"No." Dean's eyes found Sam's chest—still, and still warm. Even from this close, he couldn't hear a heartbeat. Couldn't see the merciful pulse of blood on the side of Sam's neck. "No, no, no, no…"

Dean pulled Sam in, cradled him against his chest, arms bracing Sam, keeping him from falling. He felt the walls around him crumbling, the walls that kept him from showing his brother how much he cared, how much his heart broke every time Sam was in pain or in danger. He rested a hand on the back of Sam's head, shifted them both, trying not to throw up or stop breathing himself.

"Oh, God. Oh God." He gripped the back of Sam's jacket in stiff fingers, reflexively twisting and pulling, not just holding onto his brother but holding onto the threads of his own sanity as Sam lay against his chest, head resting in the crook of Dean's elbow, gone. Sam was gone. The only thing that had ever mattered more to him than his own life, and it had just been stripped off like his own skin.

Kneeling in the street, Dean moved his arm, wrapped it around Sam's shoulders, held him close, trying to drag him into the strength of Dean's own body, begging with every ounce of life in him that Sam would just hold on.

"Sam!" Dean screamed his brother's name, and there was no response.

And it hit him. That if Sam wasn't moving when Dean called for him like his world was ending, like everything he loved was getting ripped apart, leaving him twisted and cut open and bleeding all over this muddy street, then he wasn't there. He wasn't…

Dean tangled his fingers in Sam's hair, buried his face in his brother's shoulder, and let the tears come as he watched his world fall to pieces.