Dean and Cas have fallen into the pits of Purgatory. But Cas has up and disappeared. Dean's about to panic when salvation appears to him. God put a failsafe in that will lead any human out of Purgatory. Guided by a blast from his past, Dean maneuvers through Purgatory, heading towards Cas, but more importantly, Home.

( Part 1 of Brothers Apart ) Sam was hit with a curse when he was 10 and Dean was 14. Unable to find him or his attacker anywhere when the dust settled, John and Dean Winchester were forced to give him up for dead.