Release Message:  Castiel sends Dean (Jensen Ackles) back in time to 1973 where he encounters younger versions of his parents and for the first time meets his grandfather Samuel Campbell.

Description:  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. Wikipedia: Dean is sent back in time by Castiel to investigate events concerning his parents as teenagers.