Sam and Dean's life is changed dramatically when every single aspect of their life stops. They stop hunting, and the demons and monsters stop appearing. They decide to move to Atlanta, Georgia, only to have another problem be awaken. When the boys wake up to find the whole city evacuated, they know something is wrong.
(Most of this will follow the story of The Walking Dead, so do not accuse me of copying, because I am just following the storyline. On the other hand, I will put change some of it up to make it different, don't worry :D)