Note: I know there are a lot of Dean and Sam separated at birth stories, but I hope that this one is a different view on it. It's kind of a dark view of Dean.
Dean Winchester was a pro. He could flirt and charm his way to anything he wanted. Which came in handy with the job he did. He kept it up full force in the light of day. He flirted with any woman who crossed his path. They'd all fall for his charm. He'd occasionally go home with one of them. Amusement was almost always dancing in his dark green eyes.
It was at night when it changed. He'd pull into another dingy cheap motel and book a room with a credit card that wasn't really his. He'd go into his room and ignore the stains on the walls and ceilings. He'd throw his bag on the floor by the bed and drop into it on his back and stare blankly at the ceiling. If you watched his face, you could see it then.
Dean's eyes, as soon as he hit the pillow, changed. The amused light left. His eyes turned cold and hard. Emotion drained from his face, leaving it impassive. Exhaustion hit like it always did. It was draining, keeping up the act. He sighed and wondered if he had enough energy to take a shower. Deciding against the idea he slipped out of his jeans, flipped over on his stomach, and almost instantly fell asleep.
Dean Winchester was four when he stopped being a child. Watching your mother die could do that to you. He was almost five, though, when he'd started turning into the man he was now. When he'd started to hate his father. He supposed he understood on some level why John had done what he did. Giving up your own child had to be hard.
Dean didn't know for sure that it was hard, though. He knew that John felt guilty. And that he was basically broken. The man had lost his wife and youngest child, after all. So maybe that was why he treated Dean the way he did. John was basically a stranger to Dean. Dean went through the motions when he was young. When he was a small child he'd followed his dad's orders because John was his dad and he still had some respect for the man. When he'd gotten older, he'd followed orders because most of the time he'd just been to tired to fight. And because, even if he would never admit it, he was slightly scared of his father.
John had grown more bitter with each passing year. Dean knew why. They had never found the demon. Dean had begun to suspect that John had been hoping to find the demon so he could see his youngest child again. This, of course, only made Dean's resentment grow.
Dean was only seventeen when he left. The fight that had broken out between him and John when Dean had told him had been bad. John had actually hit him for the first time in his life. He'd actually looked a little horrified afterwards for a split second and Dean had had the fleeting thought that maybe John actually cared. But then John had turned back to anger and the thought had fled Dean's brain. He'd left.
Dean kept hunting after that. He didn't really know what else to do. He didn't know how to do anything else. He'd been a hunter all his life. It was dangerous, hunting alone. Especially at seventeen. He had a few nasty scars now that were a result. He'd been okay, though. Well, maybe not okay, but he had survived. His mask was firmly in place. Everyone was fooled by it. Even John had been. He'd only let it slip when he'd told John that he was leaving. He had the suspicion, though, that maybe John had known all along that Dean was faking it. He just hadn't bothered to find out. That suspicion had added to the reasons why Dean had left.
It had been a few years later when he'd seen John again. The man had looked even more broken, if that was possible. Dean had felt a flash of guilt, but by that time Dean had started having trouble feeling much of anything but anger and despair. He hadn't fought John when the man insisted that they at least keep in touch. And after that they did. Sometimes when John would call after one of his hunts, Dean wanted to scream at the man. Ask him if he was proud of what his son had become, of what John had made him into. Because, that was the root of his anger, wasn't it? He hated himself, what he'd become. And he blamed John.
Sam drove into the small town and looked around. He chewed his lip in thought. Bobby had said that the man was here. He just needed to search the motels in town. Bobby had warned him that the man wouldn't trust him and might not even listen, but Sam didn't really have a choice. His hand clenched on the steering wheel of the rental car.
When Sam had woken up to find his girlfriend pinned to the ceiling of his dorm room, he had panicked. He'd frozen. In fact if it weren't for Bobby, he probably would have died. The older man had pulled him from the fire. Sam didn't know why the man had been there, but he had been. Sam had watched his girlfriend die. And he had to face the realization that he'd dreamed about it before hand. That his dreams had come true.
Bobby had told him a lot of things after that. He'd told him about demons and spirits. Sam should have been shocked, freaked out. But it seemed like Jessica's death had taken it all out of him. Determination was left, though. Determination to find what had killed Jess.
Bobby had told him about another hunter who had been hunting the same demon for over twenty years. Bobby had convinced Sam to go to this other man. So that was what Sam was doing. But in the end it didn't matter, he supposed, if this man turned him away or not. Nothing would stop him from hunting this thing down.
Note: Before you get on me for the whole Dean disobeying John thing, Dean did say in the first season that the reason he follows John is because the one time he didn't Sam almost died. That obviously didn't happen here.