It all comes down to the final battle in 'Supernatural' May 14 finale, Sam goes with Ruby while Dean teams up with Castiel and Zac.
The season finale of "Supernatural" will air next week, May 14 with the apocalypse finally arriving. Sam and Dean prepare for the fight in very different ways. Sam joins Ruby on a final run to kill Lilith (guest star Katherine Boecher), while Castiel and Zachariah (guest star Kurt Fuller) tell Dean it's time to play his part in stopping Lucifer.
Creator Eric Kripke who directs the episode, has shared some hints to TV Guide regarding the characters on the verge of Apocalypse. He said, "The Apocalypse is coming down to the wire, and it's time for Dean to play his part. While we're on the subject, besides Zach and Cass, a lot of the Angel gang are coming back. Anna makes an appearance, and even the Prophet Chuck pops in for a bit."
He also confirmed that there will be a "big cliffhanger" as well as major deaths that will affect the storyline of the fifth season.