Supernatural: Season 4, Episode 21 - ProjectFreeTV

4 - 21: When the Levee Breaks

Dean and Bobby lock Sam in Bobby's panic room so he can detox from the demon blood. However, as Bobby sees more seals are being broken he tells Dean they should let Sam out to help them fight the impending apocalypse. Dean disagrees and goes to Castiel for help. Sam and Dean have a big blowout confrontation.