"I'll stay here and watch him."

Peter's voice right behind him made Dean start. The absolutely murderous glare Sam aimed first at Dean, then at Peter was scary. Not that Dean thought for a second Sam might hurt him, but he wasn't so sure about Sam hurting Peter. In fact, given the opportunity, Dean was pretty darn sure Sam would do substantial harm to Peter.

In the span of time it took the thoughts to form, Dean realized he'd gone from protecting Sam from the world to protecting the world from Sam.

The back of his throat stung and burned, moisture oozed along his shoulders as Dean managed to get control of a sudden shiver wanting to rage uncontrolled through him. Sam never wanted to hurt things, he wanted to save them, help them. Dean's mind was barely beginning to wrap around the thought his quiet, kind brother wanted to kill a child. Murder a child.

"I'm not—" The words spat from Sam's mouth.

Dean held up one hand, fingertips against Sam's chest, silencing him. Twisting far enough to see Peter, he made sure both Sam and Peter heard what he said. "That's nice, and I appreciate the sentiment."

"Dean!"

Pushing against Sam with enough force to move him back a step, Dean smiled at Peter. "Like I said, that's kind, but not necessary." He took a deep breath. "Listen, Peter, I need to talk with Sam. Alone."

The spark of antagonism, pure hate, arcing between Sam and Peter for a few seconds made Dean want to cringe away from them both. Not moving his feet or his body took tremendous conscious effort. In that span of seconds Dean wasn't sure from which boy it originated, or who was afraid of whom. Again, something cold and aggressive bloomed in Peter's eyes, dying away as soon as Dean could register it was there.

Sam surging against the gentle pressure of Dean's fingers when Peter didn't move away immediately caused Dean to step towards Sam. He forced them both to take another step back. He felt Sam's entire body twine and quiver against Dean's restraint. Sam could certainly get around Dean if he wanted, three fingertips against Sam's chest wasn't nearly enough to hold him back, yet it was.

A weapon is only as good as the man who wields it.

Peter nodded, smiled up at him and turned away, silently moving to the opposite end of the bunker.

Dean's mind skipped back to before. To the time prior to his being thrust into Hell. The thing, Ruby called it a bomb, inside Sam, that was Sam, whatever, mercifully hadn't fully surfaced since. At least not to the point they couldn't handle. Sam may very well be some weapon. Dean was beginning to see he couldn't ignore that any longer. Not with glass exploding around Sam. He was also seeing, if Sam was a weapon, Dean was the trigger, Dean was who wielded the weapon.

It was becoming crystal clear to Dean, what power he had, wanted or not. Here he was keeper of some weapon, demonic or powerful enough to combat demonic, he still wasn't sure. But keeper of it he was. He had two choices, as he saw it. He could either chose to be guardian of that weapon, or its destroyer. Guardian he'd been since the first time Sam drew a wailing newborn breath. Destroyer? That was never, ever an option.

When he looked back on the last hours before his meeting with Hell hounds Dean realized it was there then, the clues, his control over the weapon that was Sam Winchester.

Exploding glass was one thing. It was the thought Sam might be able to explode heads, specifically Peter's if he deteriorated, regressed far enough, that sent ice through Dean's intestines. The idea Peter might also do something to Sam chased right along on the heels of Dean's thoughts Sam might harm Peter.

Taking a few more steps, shoving Sam backwards until they were behind one of the partitions they'd set up.

"I do not need a freaking damn babysitter!" Sam was literally vibrating with anger. "There is no way I'm staying here waiting around to see if you come back."

"Sam, the last thing I'd do is leave you alone with him or anyone after what you turned into—"

"Turned into what?" The challenge and anger left and Sam's voice cracked into pieces over the last word.

Running one hand over his face, Dean drew in a deep breath, put up a placating hand. "Sorry. Bad choice of words." Ever since they'd gotten here Sam seemed to be a half step out of sync with the rest of the world. In a blink the difference would be gone, and Sam would be Sam again. "You haven't exactly been in control."

Sam's gaze dropped to his feet. "I'm sorry."

Dean removed his hand from Sam's chest. Let it sit solidly on his shoulder. "It's not your fault."

"You promised."

The way Sam's voice sound tiny and lost made Dean's chest tighten, a large blob filled his throat. "You're better in here." He barely managed to push the words out, not even caring how his own voice sounded lost and pleading, how it cracked.

"What if you don't come back?" Sam pinched the bridge of his nose between two fingers. Dean saw one stray, rebellious tear get free. "What if you go out there and disappear too because we're not together? You look at me and you promise me that if I stay you'll come back. You promise me that."

The wind completely left Dean's sails and his resolve. He couldn't make that promise. He wouldn't lie to his brother that way. Not now, not ever. If he was seeing things because of Sam's proximity, what was to stop him from vanishing if they separated? What was to stop the same from happening to Sam? He didn't want to leave his brother here, not at all. Dean did, however, want his brother safe and whole. Out there he was neither. Out there he teetered on the edge of some sort of insanity.

Out there they were together.

"You promised." Sam whispered.

He had. He'd promised a little boy who was inside the grown man that was his brother they'd stick together. Both those parts of Sam feared losing Dean, maybe more than Dean feared losing Sam. Every one around Sam died horrifically, and Sam watched. Dean had been given a second chance, he wasn't sure why, but he wasn't going to let Sam suffer that again. He wasn't going to abandon Sam either, let him sit alone and wondering.

A little voice in the back of Dean's mind told him, repeatedly, they were stronger, safer together. It had always been that way, always would be that way. He had promised, and if his promises were empty, then what sort of man, what sort of brother, was he?

Sam had totally played him, and Dean knew it. In a way he was grateful for it.

Smokey Mountain Inn…

They'd been about halfway back to town when Dean, and possibly Ernie, realized bringing Sam had been a horrible, grievous mistake. They probably shouldn't have brought Peter either, but both were in agreement, Peter and Sam left alone together was a sure recipe for tragedy and disaster.

The road between Ernie's bunker and the town was littered with evidence of violence and desperation. Vehicles abandoned and bloodied, a few bodies. People's possessions scattered along the roadside. It was heart wrenching.

By the time they pulled into the town, Sam was bouncing up and down in the seat beside Dean, tugging on Dean's sleeve. Rapid fire questions shot from the kid's mouth about what they witnessed going on around them. People were stealing things, attacking one another, some sitting in the middle of the road sobbing. Dean had no answers. All he could do was pull Sam's hand from his hair and push him back against the seat to quiet the rocking motion.

Dean's eye caught Ernie's in the rearview mirror. He entertained the thought of asking Ernie for a length of rope and literally tying Sam to him. This was worse than it'd been since they'd arrived. Sam chattered on like a toddler, "promised me," was interspersed every few sentences.

Ernie stopped the truck in front of their motel, the Impala a few spaces down. "Look, you want me to keep an eye on things in here?"

Grateful for Ernie's tact, Dean darted a glanced at Sam and started to nod. The second he reached for the door handle, Sam snatched his jacket with both hands and scooted across the seat to follow Dean out the door.

"Sammy, I really need you to stay in here with Ernie."

Shaking his head furiously, hair flapping in more directions at once than Dean thought possible, Sam's grip on his jacket tightened. "Promised me, promised me, promised me. You promised me!"

Dean sighed. "Don't take your hands off my jacket."

He and Sam more tumbled from the backseat of the truck than climbed down.

"Can we go check for my mom again?" Peter asked Ernie.

Ernie's eyes again met Dean's.

Nodding, Dean waved at their motel room door. "It'll take us ten minutes or so to pack everything up."

"We'll be back in less." Ernie restarted the truck and pulled away from them, heading towards Peter's house.

"We have to go see Lynn. Please, Dean? Please?" Sam tugged at his arm, bounced on his toes, all the while eyes darting everywhere at once. "We have to, please, Dean? Dean?"

"Yeah, Sammy, first we have to get our stuff packed in the car."

It took them five minutes. Dean ignored how the entire time Sam kept up a steady chant…promised me, promised, promised, see Lynn, need to see Lynn, promised me. Grinding his teeth together to keep from snapping at Sam to just shut the hell up, Dean grabbed bags in one hand, Sam in the other and dragged his brother to their car.

Opening the driver's side door, Dean threw their bags over the seat to the back. In the next move he shoved Sam into the car.

Screeching loud enough to make Dean jump and turn for a look around them, Sam hit the steering wheel.

"NO!" He shouted, fists hitting the steering wheel again and again. "Not driving, not driving, no, no, no."

Grabbing Sam's closest wrist, Dean tried shoving him across the seat. "Sam just move over. I'm driving!" No way was he even thinking of getting Sam to drive, even if he'd been capable of it.

He still had the small cut on his forehead from a week or two ago when he'd tossed Sam the car keys, thinking he'd like to drive for a bit. To Dean's utter surprise Sam volleyed them right back, accidentally hitting him in the head, leaving a tiny cut. Sam had stood there and screamed at Dean he never wanted to drive that car again. The whole thing caught Dean by surprise and off guard until he'd worked out it was another of those moments of panic Sam kept so well buried. Dean had always primarily drove. It was Dean's job to drive. He liked to drive. Sam merely tolerated it when he needed to.

The last time Sam drove the Impala it'd been with Dean's dead, mutilated body as the backseat passenger.

"NO!" Sam bellowed again.

Sam may have been mentally about the age of three right now and having a temper tantrum, but he still had the body and weight of a twenty-five year old man, one in shape and with a vicious punch. Completely panicked, Sam's fist plowed into Dean's middle, shoving him away from the car, and forcing him to release Sam's wrist. Sam scrambled from the car shouting not driving, not driving, not driving.

Sucking in air, trying desperately to refill his suddenly emptied lungs, half doubled over Dean latched onto Sam's shoulders with both hands.. "Sammy," he wheezed out. "You're not allowed to drive. I just want you in the car." He managed to straighten completely and shove Sam around to the other side of the car. Opening the passenger side door, Sam looked from him to the car and back again.

When Dean waved to the inside of the car, Sam immediately quieted down and slid inside. "Need to find Lynn."

Dean braced on arm against the roof of the car and sagged against it. His other hand followed Sam inside the car. He rested it on the top of Sam's head. "We will, Sammy. We will."

A woman's scream ripped across the parking lot. Dean swiveled to find the source of the sound. Sam's head poked out of the car. A man had a woman forced back and held to the wall of the next building over. He was ripping at her clothes, then he slapped her across the face.

"Hey!" Dean pushed away from the car. He got three steps before he turned and ran back just in time to shove Sam back into the car. "You stay there. Sammy, you stay there no matter what happens."

"Promised. Promised me. Promised me."

Dean sprinted at the man and woman, twisting his torso and pointing back at Sam as he ran, "You stay there!"

Leaping a short concrete divider, Dean was landing his hand on the man's shoulder, yanking him off the poor woman. He spun the guy around, and smashed his fist into the guy's face. The man brought both hands up, crashing them into the side of Dean's head. He staggered back a few paces, stunned. The world spun and started to slip away. A second later he regained his balance and pushed a feeling of heaviness from his limbs.

The windows of the building cracked, groaned, shattered and splintered, flying in all directions.

Dean got a glimpse of Sam's fingers digging into the man's shoulder, pulling him away. The woman ducked, sobbing she stumbled into Dean. He shoved her to the ground. Covering his head with his arm, Dean pushed her into the wall with his leg, at the same time turning to Sam and the man.

Sam had barely let go, and turned away when bits of glass bounced off the denim material covering his shoulders.

"Find Lynn. Promised me." Sam started backing away.

"Sam!"

Shaking his head, Sam backed away more.

The man groaned and started pushing off the ground. The woman sobbed louder.

"Are you all right?" Dean didn't mean to shout at the poor woman, but he couldn't stop his voice from coming out loud and harsh. She looked up at him, wide eyed, with tears streaming down her cheeks. Scooting away from him, she nodded. Dean turned from her, hauled the man to his feet and hit him hard enough to knock him out. "You stupid piece of shit." Letting the guy go, he crumpled at Dean's feet.

Jumping over the now unconscious man, Dean shouted again, "Sam!"

Halfway between him and the car, Sam stopped, turned and watched Dean with round, terrified eyes. He waved at the road leading to the diner with one hand, the other gripped his hair, tugging and pulling. "We have to stop it. Help them. Promised me, stick together, promised me. One, one, one, zero, two, two, two, two." Sam let go of his hair and held both hands up in front of his face, as if holding something between them, face contorting to a snarl. "Kill him. Feel it, his neck snap, bones break, I can feel it."

Running full tilt at Sam, Dean tried reaching out for him, but Sam darted away. "Sammy, c'mon. Come here." Panic gripped Dean and nearly consumed him. His fingers felt icy, his head muddled and his reflexes too slow. Desperation took over, he had to get a hold of Sam, get him back to Ernie's bunker or he'd melt down completely and not survive, Dean was sure.

"Promised me. Stick together. Safe together. Promised me." Sam shook his head, backing away.

"Sam." It was nothing more than a whisper.

"Promised." Sam whispered back before he turned and ran.

"Shit. Shit!"

Keeping track of Sam acting like a toddler was worse than it had been when he'd actually been one.

Dean didn't even think about it, he bolted after Sam.