This season changed everything. Castiel, an Angel of the Lord, pulls Dean "out of perdition." We learn that Sam’s demon-blood-chugging is actually part of a plan to break the 66 Seals, which will release Lucifer from his cage.
When Eric Kripke first introduced us to two brothers in a black ’67 Chevy Impala, few could have predicted that Supernatural would become the longest-running sci-fi/genre series in American history. The first nine seasons represent a massive evolution—from "urban legend of the week" to a cosmic battle between Heaven and Hell. The Kripke Era (Seasons 1–5): The Apocalypse Arc Supernatural all seasons 1- 2- 3- 4- 5- 6- 7- 8- 9
Season 8 alternates between flashbacks (Dean’s time in Purgatory with a new hunter, Benny) and present day (Sam’s life after abandoning Dean). The main plot involves the “Trials of Hell” – three tasks that can close the gates of Hell forever. The human sacrifice required is massive. This season changed everything