Sam and Dean prepare for Lucifer's arrival only to find themselves on a plane flying overhead. Castiel is destroyed by the Archangel, and the brothers are left to work with Bobby to pick up the pieces and take on angels and demons alike as Zachariah reveals his master plan.
Songs: AC/DC -- Thunderstruck
While Castiel hunts for God to stop Lucifer, Sam and Dean are called to River Pass, Colorado, where Rufus, Ellen, and Jo are battling an invasion of demons.
Sam gives up hunting but several visitors in his new life makes his vow difficult to keep. Meanwhile, Castiel seeks out the archangel Raphael to learn the whereabouts of God, and asks Dean to help him.
Songs: Lynyrd Skynyrd -- Simple Man
After Dean refuses Sam's offer to team back up, Zachariah transports Dean five years into the future to witness the Apocalypse after Dean refuses to become a vessel for Michael. Humans transformed into zombies by the Croatoan Virus roam the earth and Dean's future self and a small band of rebels are mankind's last hope against Lucifer himself.
Sam and Dean take on their first post-reunion case when a man is killed in a head-on collision... in a parked car in a garage. The brothers soon realize that the killer is taking on the appearance of famous real-life icons and killing their greatest fans, and a wax museum holds the key to locating the killer.
Songs: Jeff Beck -- Superstition
Urban legends and children's imaginings become real in a small town, and Sam and Dean track the source to an 11-year-old boy who can alter reality with a thought. Castiel arrives to warn them that the child, half-human and half-demon, is too dangerous to live.
Sam and Dean try to track down a male witch running a poker game where the stakes are years off the players' lives. However, Bobby finds the game first and loses. When Dean antes up to win back his friend's years, he loses as well and now only Sam can win the day.
While investigating a decapitation in Ohio, the brothers discover that the Trickster is responsible, and has pulled them into a TV reality where they are forced to play out the roles of TV characters to escape... or die.
Glen A. Larson & Stu Phillips -- Knight Rider Theme, Anya Marina -- Move You, Anya Marina -- Not a Through Street, Renee Stahl -- Something Real, The Who
-- Won't Get Fooled Again
Sam and Dean are tricked into attending the world's first Supernatural fan convention, where Chuck Shurley is the guest of honor. Bemusement turns to surprise when they discover that several real ghosts are haunting the live role-playing ghost hunt.
Lucifer prepares to summon a Horseman of the Apocalypse and Sam, Dean, Jo, Ellen, and Castiel try to stop him. However, they are soon divided and under siege by Meg, and time is running out for humanity.
Sam and Dean investigate a series of deaths at a mental hospital caused by a supernatural force. The only way they can get in is to go undercover as patients, and they soon discover they have some issues to work out.
Three teenagers decide to collect on the bounty on Dean's head, placed by Lucifer, by one of them switching bodies with Sam. While Sam has to deal with domineering parents and high school, Dean discovers that "Sam" has a new enthusiasm for the monster-hunting profession.
Songs: Bob Seger
-- Rock And Roll Never Forgets
Anna travels back in time to kill Mary and John Winchester before they can conceive Sam and Dean, thus preventing the apocalypse. Castiel transports the brothers back to save their own parents, but they must answer awkward questions when their parents begin to wonder what's going on.
-- Cherry Pie, The Eagles -- Life's Been Good
Lovers begin to kill each other in a small town on Valentine's Day. However, when Sam, Dean, and Castiel investigate, they discover that people are not just starved for love... and Famine, one of the Four Horseman, is fueling their hunger.
In Bobby's hometown, the dead raise from their graves... and take up their normal family lives where they left off. Sam and Dean suspect something sinister is responsible, but Bobby refuses to investigate... and they discover that his dead wife Karen has returned to him.
When two angry hunters kill Sam and Dean, the brothers find themselves in Heaven, surrounded by their best memories. However, Castiel contacts them and says that they need to find the Garden and talk with Joshua, the one angel who speaks with God. However, to get there, the brothers must evade Zachariah... and meet some familiar faces.
Songs: Bob Dylan
-- Knockin' On Heaven's Door
Sam and Dean find a town where the angels have chosen a pastor's daughter, Leah, as a prophet to teach the townsfolk how to fight demons. However, the town is soon swept up in a religious fervor as Leah passes on the angels' increasingly strict commandments, and struggles break out between the chosen and the "sinners."
Dean is ready to give in and allow himself to be used as a vessel by Michael. However, Zachariah is given a second chance and comes up with a plan to turn the Winchesters' family bond against them by recruiting a new vessel.
Earth's pagan gods gather and trap Sam and Dean in a hotel. While they try to decide what to do, Gabriel arrives, pretending to be Loki, and tries to keep the gods from engaging in futile battle. However, one of the gods turns traitor, endangering everyone and forcing Gabriel to make a decision.
Crowley contacts Sam and Dean and offers to help them find Pestilence so they can get the third ring and trap Lucifer. They capture the demon in charge of coordinating the Horsemen's activities, but Sam realizes that the demon is an old acquaintance.
After Bobby and the brothers recover Castiel, they search out Pestilence, who is preparing to unleash the Croatoan virus upon the planet. While Sam, Bobby, and Castiel go to stop the distribution, Dean and Crowley travel to Chicago where Lucifer is using Death to create a storm that will wipe out three million people on Death's behalf. However, Death has a plan of his own.
Songs: Jen Titus -- O Death
When the Winchesters run out of options, Sam decides that he must open himself to Lucifer and hope that he can maintain control long enough to seal Lucifer away. However, he soon discovers that he is in over his head, and his brother and friends must pay the price.