You are Sam and Dean's little sister. It's been six months since he went to hell, and he just appeared at your and Sam's doorstep alongside Bobby while you were out and Sam wasn't home. Not trusting this is the actual Dean, Sam takes extra precautions. Bobby and Sam tried stabbing Dean with silver and splashing him with holy water. Turns out he's the real Dean, returned from hell. But you don't know that. You're in shock as you see Dean standing in your and Sam's house,Bobby and Sam behind him.