The name Dean (Jenson Ackles) gives to John (Drake Rodger) and Mary (Meg Donnelly) is James Hetfield. Hetfield is the lead vocalist, rhythm guitarist, co-founder and a main songwriter of heavy metal band Metallica. Sam & Dean have a history of using musician's names as their alias throughout Supernatural.
Jensen Ackles, who plays Dean Winchester in this episode, and Tom Welling, who plays Samuel Campbell in this episode, worked together in season four of Smallville. Ackles played Jason Teague in Smallville while Tom Welling played Clark Kent.
The episode title is taken from the song of the same name by Leonard Cohen, which was originally recorded and released by Judy Collins in 1967.
Final episode of the series. it was canceled by CW after 13 episodes