Dean and Bobby anxiously wait for Sam to wake up to see if Death was able to restore his soul without causing Sam to lose his mind. Meanwhile, Dean and Bobby investigate a disappearance of virgins and discover dragons are behind the kidnappings. Bobby sends Dean to a doctor who owns the only weapon in the world that can slay a dragon, but Dean must prove himself worthy enough to take it

Eve, the Mother of All, unleashes a new monster upon the world: a black worm-slug that can enter the brain and force people to kill. Sam and Dean join forces with Bobby and Rufus and track it to a cannery, only to discover that Gwen and Samuel are also there looking for the monster... and none of them know who the monster is inside.

Sam, Dean, Bobby and Castiel track Eve to a small town in Oregon. The guys discover the townspeople have been converted to demons, but surprisingly, they all appear to be dying. When they finally do meet Eve, she decides to torture the brothers by bringing back their mother.