Bobby tells Dean and Sam that Castiel has stolen the Moishe Campbell Diary, but he has a copy. They read the journal and discover that in 1937, H.P. Lovecraft had opened a gate to Purgatory with five worshipers of the devil. Meanwhile Crowley abducts Lisa and Ben to force Dean and Sam to step back. Sam summons Balthazar and the angel is surprised with the revelations about the partnership of Castiel with Balthazar. While Dean and Sam seek out Lisa and Ben, Bobby investigates what happened in 10 March 1937 and discovers the truth about his friend Ellie. Balthazar brings Dean and Sam to an angel-proofed warehouse where Lisa and Ben are captive. When Dean is ready to rescue them, he discovers that Lisa is possessed by a demon.