Hi there,
I am looking for a story I read about four years ago. It's post apocalyptic. Sam rules a kingdom on earth and somehow Dean is there with him but I THINK he is mute, but maybe not and acts as Sam's hound. Not a dog, but scouts for him and fights for him. I think Meg or Ruby are there too. They are fighting a battle against the last free humans on earth.

I don't remember a lot about this story, but in the end Dean betrays Sam and goes to work for the human's. Rather than lose Dean, it forces Sam to change his mind and come along side him.
I know this description is super vague, but any help finding this would be appreciated

FOUND:
Dare Frame thy fearfull symmetry by keerawa on LJ
Also on AO3 (link thanks to dinkwerks)