When Dean emerges from purgatory, his reunion with Sam isn't what he expected; Kevin escapes from Crowley's grasp.
When Sam and Dean check on Kevin's mother, they discover that Crowley has surrounded her with demons.
Sam and Dean investigate a series of murders where the victims all received organs from the same donor; the brothers find the killer in a trance and reciting an ancient prayer.
As Dean and Sam investigate a strange murder in a college town, they discover two dead bodies and disturbing video footage.
After Benny is brutally attacked by vampires, he calls Dean for help; Sam reflects on the life with Amelia he left behind.
As Dean and Sam investigate a murder, they find Garth (D. J. Qualls) is already on the case; the guys search for an avenging ghost.
Kevin and Mrs. Tran build a demon bomb; Dean and Sam are shocked when Castiel appears.
Castiel tells Sam and Dean that he has decided to become a hunter like them; the guys investigate a series of murders that resemble cartoon deaths.
Sam secretly asks a hunter named Martin to watch over Benny; Dean is forced to make a difficult decision.
Castiel must rescue an angel being held captive by Crowley; Amelia meets with Sam and asks him to make a choice.
Dean and Sam investigate when two people die mysteriously while playing a game of "Moondoor"; the guys learn that Charlie is the queen of Moondoor.
A man claiming to be Henry Winchester appears in Sam and Dean's hotel room and demands to know where John Winchester is; Dean and Sam learn more about their father and their family history.
Sam and Dean investigate when a rabbi spontaneously combusts; a golem belonging to the rabbi's grandson attacks Sam and Dean.
Kevin figures out how to close the gates of hell after deciphering the tablets; Sam and Dean argue over who should complete three trials designed by God.
After turning to witchcraft, a police officer named Kevin starts having nightmares in which he murders innocent people; when the murders start happening in real life, Sam and Dean investigate.
Sam and Dean investigate a possible zombie case where an amnesiac man dies and revives himself once a day.
Castiel tells Dean and Sam that Crowley has unleashed multiple demons in a small town; during an interrogation, the guys learn that Crowley has been torturing Meg.
Dean and Sam are surprised when they learn that Krissy Chambers was involved in some recent vampire deaths.
A terrified Kevin calls Sam and Dean after he hears Crowley's voice in his head; after Dean receives a visit from Naomi, he realizes he needs to ask Benny for a favor.
Dean asks Sam to stop hunting until he recovers from the second trial; when a hacker (Felicia Day) stumbles upon a case, Dean teaches her how to be a hunter.
When Dean and Sam receive an upsetting video message from Kevin, they decide to try and uncover the third trial; Castiel tries to get away from Naomi and the angels.
When Sam and Dean reunite with Castiel, they find a film that could be the key to the third trial; Crowley looks into Dean and Sam's past.