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.
4 - 1Lazarus Rising Sep. 18, 2008- 4 - 2Are You There, God? It's Me, Dean Winchester Sep. 25, 2008
- 4 - 3In the Beginning Oct. 02, 2008
- 4 - 4Metamorphosis Oct. 09, 2008
- 4 - 5Monster Movie Oct. 16, 2008
- 4 - 6Yellow Fever Oct. 23, 2008
- 4 - 7It's the Great Pumpkin, Sam Winchester Oct. 30, 2008
- 4 - 8Wishful Thinking Nov. 06, 2008
- 4 - 9I Know What You Did Last Summer Nov. 13, 2008
- 4 - 10Heaven and Hell Nov. 20, 2008
- 4 - 11Family Remains Jan. 15, 2009
- 4 - 12Criss Angel Is a Douchebag Jan. 22, 2009
- 4 - 13After School Special Jan. 29, 2009
- 4 - 14Sex and Violence Feb. 05, 2009
- 4 - 15Death Takes a Holiday Mar. 12, 2009
- 4 - 16On the Head of a Pin Mar. 19, 2009
- 4 - 17It's a Terrible Life Mar. 26, 2009
- 4 - 18The Monster at the End of this Book Apr. 02, 2009
- 4 - 19Jump the Shark Apr. 23, 2009
- 4 - 20The Rapture Apr. 30, 2009
- 4 - 21When the Levee Breaks May. 07, 2009
- 4 - 22Lucifer Rising May. 14, 2009