Quick tag to 7x3, The Girl Next Door.
Disclaimer: Supernatural characters, etc. belong to the actors, writers, producers, directors, and crew who create the show, not me. But I'm grateful they do it!
Always
Dean climbed wearily out of the Impala and trudged toward their motel room. I'm getting too old for this, he thought. He could almost hear Bobby's snort and answering, 'you think you're getting too old?' He was debating the wisdom of entering the room loudly enough to wake Sam when a voice behind him stopped him.
"Winchester."
Turning, Dean saw a young man, still a teenager really, standing a dozen feet away. "Can I help you?"
"I promised you that the only person I'd ever kill was you. I'm here to make good on that."
Comprehension blossomed on Dean's face, quickly chased away by regret.
"Ah. Jacob. I was wondering when you'd show up." Dean pursed his lips. "So have you killed anyone?"
"I told you I wouldn't. Besides, haven't you been checking up on me?" The boy sneered at him.
"Yeah, yeah, I have. I know you've been good. Did you consider that killing me is not a good way to start? Because listen, you kill me, you get a taste for it, and then it's all over. Eventually some hunter will take you down."
The young man raised his arm, gun in hand. A slight tremor betrayed him, but he forced his hand steady, finger on the trigger.
"I thought about it, Winchester. That's why I'm not going to kill you my way. I'm going to shoot you once in the heart and then the head. Then I'm going to walk away. Just like you did."
Dean considered his options. He was too far away from Jacob to go for the gun without getting shot. If he charged for their room, it would put Sam, possibly sleeping, in danger too. But the choice was taken from him.
A shadow loomed out of the night, behind Jacob. There was a shink and Jacob's eyes opened wide.
Sam's voice came out of the darkness, "I'm sorry, Jacob. I can't let you do that."
Dean watched Sam cradle the boy as they both slid to the ground. Sammy gently brushed the hair out of the boy's eyes as he held him.
"I'm sorry. I'm so sorry. I wish it could be different. You understand?" They both saw the moment when the boy died. Sam sighed and stood with Jacob's body in his arms. "Help me get him to his car," he said to Dean.
"Sam, I... how did you know?"
"That you went back and killed Amy? I've always known that you didn't trust me – or maybe trust her – I'm not sure which – enough to just let her go. I also knew that you'd never be able to kill Jacob because he would remind you of Ben. I knew someday I'd have to take care of it for you, just like you took care of Amy for me." He glanced at the boy in his arms, then back at his brother.
"I just wish we didn't have to, you know?" A tear slipped down Sam's cheek.
"I know. Yeah, I know." Dean found keys in Jacob's pocket and they located his car. Sam lowered the body into the passenger seat, then moved around to the driver's side. Dean swallowed hard. He looked at his brother and said, "Thanks."
Sam nodded and took the keys. "You'll follow?" he asked.
"Yep." Dean headed for the Impala.
"And Dean?" Sam's voice turned him around.
When Dean was facing him again, Sam looked him hard in the eye and said, "Always."
There was nothing else to say.