Season Four consists of 22 episodes that aired on Thursdays at 9:00 pm in the United States beginning September 18, 2008, and ending May 14, 2009.
After spending four long, horrific months in Hell, Dean Winchester is miraculously raised from the Underworld and resurrected by an angel of the Lord God Himself named Castiel, one of several angels who appears throughout the season. After Dean reunites with his father-figure friend Bobby and his brother Sam, the rest of the season follows the brothers, with the help of their friend Bobby, as they work with Castiel and his subordinate and friend Uriel, a fellow angel, to stop Lilith's plan of breaking the 66 Seals to unlock a cage in Hell, which will allow the release of the fallen archangel Lucifer himself, also called the Devil, who was once the favored angel of God but rebelled against Heaven for refusing to serve humans and therefore was cast down and banished.
Along the way, the boys meet a girl named Anna who not only has the ability to hear angels but is also a fallen angel herself. Eventually, angels turn up dead and the angels capture Alastair, Hell's Grand Torturer demon who seems to know Dean well, and they ask Dean to torture him with them assuming its the demons killing the angels, but Alastair, before he dies, says its not the demons. And eventually, Castiel learns that his own brother Uriel turns out to not only be working for Lucifer, but has convinced several loyalist angels to join him and to free Lucifer from his cage. Along the way, Dean learns that he broke the first seal while he was in Hell by being convinced by Alastair to slaughter innocent souls in the Underworld, especially when he reveals to Sam that he wasn't in Hell for four months but instead 40 years. Additionally, the brothers meet a Prophet of the Lord named Chuck.
Sam and Dean's relationship is also strained as Sam starts siding with Ruby over Dean. He also begins to give into his demonic side by drinking demon blood to become strong enough to kill Lilith. After tracking down and killing Lilith, Sam learns her death is actually the final seal and Ruby was deceiving him all along. Dean arrives too late to stop him, but the brothers kill Ruby as Lucifer's cage opens up beneath them and he is released upon the world
- Misha Collins as Castiel (12/22) and Jimmy Novak (1/22)
- Genevieve Cortese as Ruby (11/22)
- Jim Beaver as Bobby Singer (7/22)
- Julie McNiven as Anna Milton (5/22)
- Mark Rolston and Christopher Heyerdahl as Alastair (5/22)
- Robert Wisdom as Uriel (4/22)
- Katherine Boecher and Sierra McCormick as Lilith (3/22)
- Traci Dinwiddie as Pamela Barnes (3/22)
- Kurt Fuller as Zachariah (3/22)
- Mitch Pileggi and Rob LaBelle as Azazel (2/22)
- Colin Ford as Young Sam Winchester (2/22)
- Rob Benedict as Chuck Shurley (2/22)
- Juliana Wimbles as Cindy McKellan/Demon (2/22)
- Brock Kelly as Young Dean Winchester (1/22)
- Mitch Pileggi as Samuel Campbell (1/22)
- Amy Gumenick as Mary Campbell (1/22)
- Matt Cohen as John Winchester (1/22)
- Jake Abel as Adam Milligan (1/22)
- Kirsten Kilburn as Lucifer (1/22)
Episode List: 2008-2009
|Lazarus Rising||Writer: Eric Kripke||Director: Kim Manners||9/18/08||#61 401|
|In the fourth-season opener, Dean has been freed from Hell and reunites with Sam and Bobby, but the three don't know how he returned.
|Are You There, God? It's Me, Dean Winchester||Writer: Sera Gamble||Director: Phil Sgriccia||9/25/08||#62 402|
|The spirits of Meg, Agent Victor Henriksen, and Ronald Reznick appear and accuse Sam and Dean of failing them, as the brothers attempt to help Bobby, who is haunted by the angry ghosts of children he was unable to save.
|In The Beginning||Writer: Jeremy Carver||Director: Steve Boyum||10/02/08||#63 403|
|Dean is sent back in time and meets his parents when they first fall in love. He also encounters his grandfather, who may be hiding a secret that is key to Dean and Sam's mission.
|Metamorphosis||Writer: Cathryn Humphris||Director: Kim Manners||10/09/08||#64 404|
|Sam and Dean encounter a man with a mysterious infection that transforms him into a flesh-eating monster. Sam thinks the man can be changed through reason to curb his newfound instincts, but Dean believes the most-humane thing to do is to kill him.
|Monster Movie||Writer: Ben Edlund||Director: Robert Singer||10/16/08||#65 405|
|Several murders occur during an Oktoberfest celebration and it's learned a shapeshifter is responsible, and that it is taking the form of iconic movie monsters, such as a vampire, werewolf and mummy. The episode is presented in black and white.
|Yellow Fever||Writer: Andrew Dabb and Daniel Loflin||Director: Phil Sgriccia||10/23/08||#66 406|
|Several men die from fright after being infected with a mysterious illness that causes acute anxiety, which leads to total terror. Sam and Dean investigate, and Dean becomes infected. Sam desperately searches for a cure before Dean dies and is sent back to Hell.
|It's the Great Pumpkin, Sam Winchester||Writer: Julie Siege||Director: Charles Beeson||10/30/08||#67 407|
|A witch sacrifices people in a small town to summon a very powerful demon who may be a key to freeing Lucifer. To stop her, Castiel brings in a special angel who intends to destroy the town.
|Wishful Thinking||Writer: Ben Edlund and Lou Bollo||Director: Robert Singer||11/06/08||#68 408|
|A wishing well is discovered to be the real thing when a girl's teddy bear comes to life, someone wins the lottery and a local geek gets a beautiful girlfriend. But Sam and Dean realize disaster waits in the wings in this town where reality and fantasy are blurred.
|I Know What You Did Last Summer||Writer: Sera Gamble||Director: Charles Beeson||11/13/08||#69 409|
|Sam and Dean search for a young woman who can hear conversations between angels after Ruby tells them a powerful demon is on the prowl to find her.
|Heaven and Hell||Writer: Eric Kripke and Trevor Sands||Director: J. Miller Tobin||11/20/08||#70 410|
|Sam and Dean learn why the angels want to kill Anna. They try to save her by helping her restore a crucial part of her past, even as Alastair and his demons close in on her.
|Family Remains||Writer: Jeremy Carver||Director: Phil Sgriccia||1/15/09||#71 411|
|Sam and Dean investigate the appearance of a female ghost in an abandoned house. But their efforts are complicated when a family moves in and the son is kidnapped through the walls.
|Criss Angel Is a Douchebag||Writer: Julie Siege||Director: Robert Singer||1/22/09||#72 412|
|A formerly famous magician living in a small town makes a deal to acquire real magical powers and pays a heavy price for it when a murder occurs.
|After School Special||Writer: Andrew Dabb and Daniel Loflin||Director: Adam Kane||1/29/09||#73 413|
|Sam and Dean investigate a series of murders at their old high school. The probe leads the two to recall how Sam was the target of a bully at school, while Dean was the big man on campus.
|Sex and Violence||Writer: Cathryn Humphris||Director: Charles Beeson||2/05/09||#74 414|
|A seductive siren compels three men to murder their wives in a small Iowa town. Sam and Dean investigate and fall under her spell, leading them to engage in a battle against one another.
|Death Takes a Holiday||Writer: Jeremy Carver||Director: Steve Boyum||3/12/09||#75 415|
|Sam and Dean visit a small town where people are cheating death because the Reapers have vanished. They journey into the spiritual world for answers and learn who is behind the Reapers' disappearance.
|On the Head of a Pin||Writer: Ben Edlund||Director: Mike Rohl||3/19/09||#76 416|
|Someone is using Lucifer's sword to kill angels. Castiel and Uriel ask Dean to use the torturing skills he learned in Hell to obtain information from a likely suspect.
|It's a Terrible Life||Writer: Sera Gamble||Director: James L. Conway||3/26/09||#77 417|
|Sam and Dean live normal, separate lives but they don't seem to know each other, even though they work at the same company. However, when colleagues start committing suicide, they team up to investigate the situation.
|The Monster at the End of This Book||Writer: Julie Siege and Nancy Weiner||Director: Mike Rohl||4/02/09||#78 418|
|Sam and Dean discover that their lives as hunters are accurately detailed in a series of "Supernatural" novels. They track down the author, who explains that he sees visions of them and turns those images into books.
|Jump the Shark||Writer: Andrew Dabb and Daniel Loflin||Director: Phil Sgriccia||4/23/09||#79 419|
|Sam and Dean agree to meet with a 19-year-old man named Adam, who claims to be John Winchester's son, but they suspect that he's really a demon attempting to trap them.
|The Rapture||Writer: Jeremy Carver||Director: Charles Beeson||4/30/09||#80 420|
|Castiel visits Dean in a dream and tells him he has important news. Dean and Sam set out on a search for Castiel, only to find his human vessel, Jimmy, who yearns for a normal life and to return to his family.
|When the Levee Breaks||Writer: Sera Gamble||Director: Robert Singer||5/07/09||#81 421|
|Sam is locked inside Bobby's panic room to allow him to detox from demon blood, but Bobby wants to free him early to help fight in the anticipated apocalypse. Dean disagrees and seeks help from Castiel.
|Lucifer Rising||Writer: Eric Kripke||Director: Eric Kripke||5/14/09||#82 422|
|The fourth season concludes with Sam and Dean preparing to fight Lucifer in the Apocalypse. Elsewhere, Sam and Ruby attempt to kill Lilith.
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