Castiel sends Dean back in time to 1973 where he encounters younger versions of his parents and for the first time meets his grandfather Samuel Campbell who holds a secret that sheds a light on the Winchester Family's connection to the hunter community.

Sam is mysteriously released from Hell and seeks out his brother who is trying to have a normal life. Together the brothers must join forces with their maternal grandfather, Samuel, and begin the fight anew.

When four families are killed and their babies are missing, Sam finds that a security company may be involved in the case and summons Dean to help him to bring the baby of a fifth slaughtered family to Samuel. However they are chased by a powerful shape shifter that wants the baby and they discover that the baby is a new breed.

When a vampire links the disappearance of a number of girls, Sam and Dean track down the bloodsucker who sinks his teeth into one of the brothers.

Dean becomes suspicious of Samuel's motives, but Sam isn't sold on the idea that their grandfather is doing anything wrong. The brothers go along on a hunt with Samuel and the other Campbells, but things go terribly awry.

Dean and Sam are captured by Meg who wants to know Crowley's hideout. Sam proposes to show where Crowley is provided she gets his soul back. The Winchester brothers ask the reluctant Samuel who has made a deal with Crowley to have his daughter Mary back but he finally points out the spot. Dean and Sam break into an old prison with Castiel, Meg and two other demons to seek out Crowley, but they are betrayed by Samuel. Castiel escapes, but Sam and Dean are arrested and Meg is tortured by Christian. Will that be the end of the quest of the Winchester brothers for Sam's soul?

Sam has flashbacks of a case he worked with Samuel; Sam and Dean follow the coordinates received in a text message to a small town, where Sam used to live; townspeople's comments surprise Dean.

When Sam, Dean and Bobby run into Rufus, and the Campbells all hunting the cause of an upsurge in supernatural activity, tensions erupt into violence.