Supernatural Season 4 Episode 21
When the Levee Breaks
Dean and Bobby have something frightening locked in Bobby's panic room: Sam, who is corrupted by demon blood. With the apocalypse drawing nearer, Bobby wants to free Sam to fight on their side.
Guest Stars
Misha Collins
Castiel
Colin Ford
Young Sam Winchester
Julie McNiven
Anna Milton
Christopher Heyerdahl
Alastair
Juliana Wimbles
Demon Nurse