The fifth season begins right where Season 4 ends with the portal for Lucifer opening. As Lucifer escapes, the brothers are teleported into an airplane by an unknown force (later revealed to be God). Later, Dean is told by Zachariah that he is "Michael's Sword," meaning the Archangel Michael will use his body as a vessel to lead the forces of Heaven against Lucifer, but Dean must consent to this. Dean refuses and Castiel saves him when Zachariah tries to force Dean to agree by harming him and Sam. Bobby gets possessed by a demon and, instead of killing Dean, he kills the demon inside himself, using Ruby's knife, in turn paralyzing himself from the waist down.
In "Good God, Y'All!," Dean and Sam fight War, one of the Four Horsemen of the Apocalypse, in a town where the people think that their neighbors are demons. In this town is Ellen, Jo, and Rufus Turner all trying to hunt the demons, who turn out to be just people that War has made eyes seem black. Once the brothers cut the ring finger off of War, restoring the town to normal, Dean worries that Sam cannot control his urge to drink demon blood, and the brothers agree to go their separate ways because Sam is a liability with...