The episode, titled “In The Beginning,” will air on Thurs., 10/2 at 9:00 p.m. ET/PT on The CW. This episode, which features guest star Mitch Pileggi (“The X-Files,” “Stargate: Atlantis”) as Sam & Dean Winchester’s maternal grandfather, begins with the angel Castiel (guest star Misha Collins) transporting Dean (Jensen Ackles) back in time to Lawrence, Kansas in 1973. In what promises to be a very revealing hour, Dean not only encounters his parents as a young couple in love, but also meets his mother’s family for the first time and learns the origin of a startling turn of events that will shape the future of the entire Winchester family – and possibly his relationship with Sam (Jared Padalecki) – forever. “In The Beginning” was written by Jeremy Carver and directed by Steve Boyum.