On this week's episode of Supernatural…
Sam's mental stability worsens with insomnia kicking in resulting in a car accident and being sent to a psych ward in a hospital.
Lucifer continues to badger Sam waiting for him to break.
Sam helps another psych patient with a ghost problem.
Dean wants to fix his brother and gets information on a man named Emmanuel who has healing powers.
Emmanuel turns out to be an amnesiac Castiel and Crowley has sent demons to capture him.
Meg, a demon the brothers' have encountered before, shows up to help Dean.
The two reveal to Castiel his true angelic nature and while defeating demons that surround the hospital, he remembers everything.
Castiel is unable to fix Sam's now crumbled wall from his destroyed soul. Instead he chooses to transfer it all to himself to save Sam.
The brothers are forced to leave Castiel behind, his mind now shattered, under the watchful eye of Meg.