What happened to Sam during the months Dean was dead? During the search for a girl named Anna Milton, who has a mysterious connection to angels, Sam reveals the astonishing events of the summer.

The angels want Anna dead, so Sam and Dean go on the run with the frightened girl, determined to discover the secret that has set the furies of Heaven on her.

Can torture be God's work? After seven angels are mysteriously murdered, Castiel and Uriel demand that Dean use the agony-inducing skills he learned in Hell to extract information from Alastair.

The body Castiel walks around in isn't his. Instead, it belongs to a regular guy named Jimmy who wants his body - and his life - back. He gets the body. But the life may be a different story.

Dean and Bobby have something frightening locked in Bobby's panic room: Sam, who is corrupted by demon blood. With the apocalypse drawing nearer, Bobby wants to free Sam to fight on their side.

The angels send Anna back in time to kill John and Mary Winchester before they can conceive Sam knowing that if Sam was never born then Lucifer won't be able to use him as his vessel. Castiel sends Sam and Dean back to 1978 so they can stop Anna, and the two brothers are reunited with their parents. Mary recognizes Dean as a hunter since he visited her in the past once before but tries to keep the truth from John.