Sam, a soon-to-be college graduate, has an interview set up to attend one of the most prestigious law schools in the country. His brother Dean, whom he has not seen in several years, unexpectedly shows up in the middle of the night to tell him that their father went missing while on a hunting trip. Leaving his girlfriend behind to find their dad, Sam joins Dean in order to find their father in Jericho, a small town where unmarried men have disappeared without a trace.
Sam and Dean head to Colorado to check out the coordinates that their father left them in his journal. When they arrive, they pose as park rangers to investigate the disappearance of three campers and soon discover that they're up against a Wendigo, a mythical creature from Native American folklore.
Dean comes across an article about a mysterious drowning. Sam and Dean soon find that several people have drowned in the same lake, but bodies were never found, suggesting that a spirit is haunting the lake.
Sam and Dean are called in to investigate a mysterious airplane crash, and soon realize that a demon was responsible. It intends to eliminate the survivors of the crash, and is willing to kill hundreds to achieve its goal.
Sam and Dean hear about a man who died of a stroke while in front of a mirror. After visiting the family and interviewing the man's two daughters, the brothers conclude that the legendary Bloody Mary caused the man's death.
One of Sam's friends, Zach, is accused of murder, and Sam offers to help him by checking up on his younger sister, Rebecca. While visiting her, Rebecca convinces the brothers that Zach didn't commit the murder because he was with him when the murder happened. But could Zach be in two places at the same time?
The brothers come across a girl whose boyfriend fell victim of the Hook Man. It's up to Sam and Dean to destroy the ghost's bones before she and her father become victims as well.
A gas & power worker is killed when insects burrow themselves into his brain and consume it. Sam and Dean research the history of the new housing development and find that it has been constructed on former Indian land cursed against the white man. Now, it's up to the brothers to get the people out before they are killed by swarms of bees, locusts, spiders, and beetles.
Sam continues to have haunting dreams and convinces Dean to return home for the first time. There, the brothers have to deal with painful memories, but their feelings are put on hold when the current residents experience the same phenomena that Sam had dreamed about. But before they can stop what's happening now, Sam and Dean have to face their mother's death first.
Sam and Dean travel to an abandoned sanitarium where they find that the patients once revolted against cruel and unusual punishments given to them by the head doctor. The brothers search the area for lost college students, but the spirits make them go insane, and end up turning Sam against Dean.
Sam and Dean part ways when Sam insists on ignoring John's orders and tracking down Jessica's killer. Dean travels to a town that's hiding a dark secret about a scarecrow, and their perpetual prosperity, while Sam meets up with an attractive hitchhiker.
During a fight with a hobgoblin, Dean is electrocuted, causing deadly damage to his heart. Sam tries to find a way to save Dean, and comes across a preacher who claims he can cure the incurable. But the brothers soon discover that the preacher's miracles are happening due to help from the Grim Reaper, who trades one life for another, "less worthy" life.
Dean and Sam travel to Missouri after Cassie, one of Dean's ex-girlfriends, calls him to investigate two racially motivated murders. They find that each murder involves a black truck that has no driver and leaves no tracks. Meanwhile, Dean has to deal with the feelings that he still has for Cassie.
Sam has a premonition about a man's death that is staged to look like a suicide. Once Sam convinces Dean to investigate the case, they are puzzled when they can't find proof that something supernatural was behind the death. However, they soon realize that the dead man's son, Max, has telekinesis and is using it to kill off his abusive family members.
Sam and Dean head to Minnesota where a young boy witnesses a man vanish into thin air. Shortly after arriving, Sam is targeted by the same abductor, and Dean is left to search for his brother. However, the brothers discover that their kidnappers are humans, using the captives as human prey for their sadistic "hunting expeditions."
While following a lead concerning a mysterious death in Chicago, Sam reunites with Meg. Sam suspects it's more than a coincidence, and Meg soon ambushes Sam and Dean. She explains that it's a trap... for John, using them as bait.
Dean and Sam track down the ghost of Mordechai Murdoch, who haunts an old Texas farmhouse. However, the brothers discover that Mordechai is a tulpa, created by thousands of people believing in it after the fake legend of him was posted on a popular website. Now, Sam and Dean must stop the spirit from killing any more people who enter the house.
When Sam and Dean find articles about a town where children are inexplicably falling into comas, the brothers discover that a Shtriga, a creature that attacks children, is behind the mysterious comas. During the battle, Dean remembers a past battle with the creature that almost resulted in Sam's death.
When a young couple mysteriously die after buying a portrait of a 1910 family, Sam and Dean travel to the scene to investigate the painting. The brothers find that each owner of the painting has ended up dead due to a dangerous spirit bound to the portrait. Can they stop it before it kills again?
When a vampire hunter and friend of their father's is killed, Sam and Dean are shocked when their father arrives to help them solve the crime. John finds that vampires have stolen a gun that has the capability of killing all evil beings. The brothers, along with their father, set out to get the gun back.
After Sam has a vision of a family being attacked by a demon, similar to the way his mother was attacked, the Winchesters follow demonic signs to Salvation, Iowa, to kill the demon using the Colt. However, Meg calls the family to let them know if they don't give her the gun, she is going to kill their friends.
To save their father, Sam and Dean enlist the help of a family friend, Bobby Singer. When Meg shows up at Bobby's home, the brothers are able to exorcise the demon from her body and get her to tell them where their father is being held. The brothers race off to rescue their father, resulting in a final showdown between the Winchesters and the demon they have spent their lives looking for.
Dean discovers that he has the crash... but is trapped as an ethereal spirit outside of his comatose body. He befriends someone else in a similar condition and tries to find a way to contact Sam and John. Meanwhile, John goes to extreme measures to save his son.
Sam and Dean receive a message on their father's cell phone from a woman named Ellen and head out to find her. They discover that Ellen is the owner of a roadhouse that serves as a meeting place for hunters. Meanwhile, a circus clown is targeting young children who will let him into their home so he can brutally murder their parents.
The brothers get the Impala running and head out to investigate a Montana case with cattle mutilations and decapitations. They end up teaming with Gordon Walker, a hunter whose motivation to destroy supernatural beings may be stronger even than theirs. Together they hunt a nest of vampires. Then Sam learns something about the vampires that might change everything and Ellen gives him some advice about Gordon.
While visiting their mother's gravestone, Dean notices a patch of cursed ground, and insists that a zombie is on the loose. Sam thinks he's just burying his grief for their mother, but Dean persists. The Winchesters eventually discover that someone has used necromancy to bring back a dead girl... but the zombie is seeking revenge on those who wronged her in life.
Sam gets another premonition of death, this time in Blue Ridge, Oklahoma. The brothers investigate and discover that Andy Gallagher is Sam's age and had a fire in his nursery when he was six months old. They soon realize that he has the power to control people, but Dean isn't convinced that Andy is responsible for a recent string of suicides.
Blond women have disappeared from an apartment building for 80 years. Jo gives the file to the Winchesters after her mother Ellen refuses to let her investigate. However, she defies her mother and joins Sam and Dean in the field, and they discover that the ghost responsible is the spirit of of H. H. Holmes, America's first serial killer, is behind the murders.
Sam and Dean travel to the scene of the murder of a lawyer and his wife who claimed to had seen a ghost prior to their deaths. But Sam and Dean don't get far when local authorities come across the brothers' record and arrest them for a double homicide. However, when the ghost begins to visit detective Ballard, the woman that arrested the brothers, she begins to think that Sam and Dean's story might just be true and she might be next.
Two miraculously successful individuals die after claiming to be haunted by hell-hounds. Sam and Dean discover that each of them visited a bar where a demon has been making people's dreams come true in exchange for their souls. They find the last person and Sam protects him while Dean summons the demon. However, he is shocked when it reveals the truth surrounding his father's death, and tempts Dean into getting the one thing he wants the most -- his father.
Sam has a vision of Dean killing a demon-possessed man. The brothers travel to River Grove, Oregon to find answers to Sam's premonition, and discover a virus-stricken town where the victims are driven to kill. Sam is infected by the virus and prepares for his deadly fate, but proves immune so Dean decides to tell Sam the truth about what John told him before he died.
When Dean tells Sam about what John told him before he died, Sam heads off to Indiana without Dean knowing. There Sam meets Ava Wilson, a psychic who was looking for Sam in order to warn him about his fate. Meanwhile, Dean tracks down his brother and discovers that hunter Gordon Walker plans to kill Sam, believing he's a monster.
At a small Connecticut inn, Sam and Dean encounter a single mother, Susan, whose daughter, Tyler, often plays with an imaginary friend. As Susan and Tyler are packing to move after selling the run-down Pierpont Inn, Sam and Dean begin to notice strange dolls with backward heads, an urn with a hoodoo pattern, and a mysterious old woman confined to the attic. Tthe brothers soon discover that the imaginary friend may be the ghost behind recent deaths of people living in the rural Connecticut town.
Sam and Dean investigate a string of robberies with disturbing similarities. In each robbery, a top-notch employee holds up and robs the business and then commits suicide. The Winchesters discover that a shape shifter is at work and try to get ahead of it at the next business it intends to hit: a bank.
The Winchester brothers look into the murders of several people who say they were visited by an angel and were simply carrying out God's will. After further investigation, Sam and Dean find that those murdered were guilty of secret crimes, but the brothers split on what they think the truth is -- Sam believes that there is an angel that caused the murdered, but Dean thinks that a demon is the cause of the deaths. However, Dean soon changes his belief when he sees the unexplainable.
A missing Sam finally makes contact with Dean, who travels to his younger brother and discovers he has no memory of the last few days... and he's covered in blood. As they retrace Sam's step, Sam begins to believe that his dark side has finally taken over.
Sam and Dean investigate a series of urban legends coming to life on a college campus. When they start arguing incessantly, they have no choice but to call in Bobby for help.
Sam and Dean come to the aid of a woman, Molly, who claims that her car went off the road after encountering a ghost. There's no sign of the car, and the brothers take Molly along to hunt down the ghost, as it becomes clear that their encounter with Molly isn't random chance.
While investigating the mysterious death of a lawyer who appears to have been mauled to death by an animal, Sam and Dean realize that they are tracking a werewolf. As they look into the death, Sam becomes attracted to Madison, the victim's secretary, and when it appears that Madison will be the next victim, Sam does all he can to protect her.
While in Hollywood taking some R&R, the brothers investigate the mysterious death of an actor who was killed on the set of a horror film. Rumors begin to fly that he was killed by a ghost, but Sam and Dean soon find that the death was a publicity stunt. However, when a studio executive and the film's producer are found dead, Sam and Dean realize that the rumors about a haunted set may be true.
When a ghost begins killing off inmates one by one at prison, Sam and Dean let themselves get captures so they can go into the penitentiary to investigate the deaths from the inside. However, when FBI agent Henricksen takes over the murder cases, the brothers soon find that getting out of the prison may be more difficult than finding the murderous ghost.
While on the trail of a Djinn, Dean wakes up one night and finds that he is in an alternate reality where Mary never died and John Winchester and his sons never hunted monsters. In this life, Sam is in law school and engaged to Jessica, and Dean has a steady job and a beautiful girlfriend. However, when a strange woman begins following him around , Dean realizes that all of the people that he and Sam saved have died, and has to decide if he wants to stay in his new life or return to reality.
Sam is kidnapped by the Yellow-Eyed Demon and finds himself trapped in a ghost town along with other children with special abilities much like his own. Sam and the others who have been abducted soon find out that the Yellow-Eyed Demon has brought them together in order to determine which is the most powerful. The Yellow-Eyed Demon shows Sam the truth behind the death of one of his parents. Meanwhile, Dean and Bobby team up to help save Sam before the battle breaks out, but, unfortunately, are too late.
Dean refuses to accept Sam's death, and makes a painful sacrifice to bring him back. Meanwhile, the Yellow-Eyed Demon uses Jake to advances his master plan to take over the Earth and Sam and Dean must track him down before it's too late.
When the gates to Hell open, seven of the demons take up shop in Lincoln, Nebraska, and start a string of bizarre killings. Two hunters, Tamara and Isaac, help Sam and Dean take care of the demons, but soon find they're being hunted as well. A mysterious blonde woman with a mystic knife also comes to their aid, but it's not clear who she's working for.
Sam and Dean go after demons targeting mothers and their children. While on the hunt, Dean runs into Lisa, a woman from his past, who has a son that reminds Dean of himself at that age. The son, Ben, soon goes missing and Dean and Sam uncover that a Changeling is kidnapping kids from the small town and taking over their form. Meanwhile, Ruby meets up with Sam and reveals startling information about his mother.
Sam and Dean receive a call on their father's cell phone telling them that someone has broken into John's storage room in New York. There, they find that a cursed rabbit's foot has been stolen and call their old friend Bobby for help. Bobby tells them that whoever has touched the foot will have good luck until they lose the foot, which will result in the person dying. Since Sam has touch the foot, Dean buys lottery tickets, but when a thief steals it, Sam's life is in danger.
Sam and Dean investigate a group of violent deaths in Elizabethville, Ohio, a town that has quickly become home to many gamblers and drinkers. The execution of each death seems to follow a particular pattern of steps. Dean finds that demons have infiltrated the town and are using persuasive powers to help the townspeople succumb to basic human instinct. Ruby and Bobby rebuild the Colt, and Ruby delivers shocking news.
A girl whom is trapped in a coma by her wicked stepmother starts a chain of murders based on fairy tales her father reads her. Meanwhile, Sam tries to get Dean out of his deal.
Sam and Dean investigate a series of drowning victims who were nowhere near the water at their time of death, but saw a ghost ship just before they died. During the investigation, they cross paths with Bela, who is being paid to solve the case by the family of one of the victims.
Sam and Dean capture Lucy, a female vampire, who has no knowledge of how she became a vampire. The brothers come across Dixon, a male vampire, who gives blood to females he meets in bars, telling them it's the "hottest new drug." Meanwhile, after escaping from prison, Gordon sets out to find Sam, but when Dixon intercepts him and turns him into a vampire, Gordon is now an even bigger threat to Sam.
It's Christmas and Sam and Dean look into the murders of people who were pulled through their chimney. While investigating, Sam learns that they are dealing with an Anti-Santa, a demon that has roots in pagan lore. When Dean wants to have an old-fashioned Christmas, Sam has flashbacks to a Christmas where he waited for his father to come home with one special gift.
A neighborhood group of witches secretly practice harmless rituals... until one of them kills another neighbor woman.
Dean, Sam and Bobby are forced to confront their internal demons when they go up against a killer who can trap and kill people in their dreams.
While investigating the disappearance of a missing man, Sam and Dean have to break in to the place where he disappeared, but they get caught, and Dean is shot and killed by the owner. When Sam wakes up the next morning he is shocked, Dean is alive, but as the day continues Sam realizes that they are re-living the previous day so he tries to stop Dean from getting shot, but he fails and Dean dies again... and again... and again, so Sam has to learn how to continue on without his brother.
Sam and Dean break into Bela's apartment to find the Colt, but Agent Henricksen is on the scene and arrests them both on the spot. While Sam and Dean are locked up in a jail in Colorado, a demon breaks in, kills the police, and possesses Henricksen. After the brothers do away with the demon, the FBI release release them, only to learn from Ruby that the jailhouse is surrounded by demons who want Sam dead.
Sam and Dean end up appearing on Ghostfacers, a reality TV show created by ghost hunters Ed Zeddmore and Harry Spengler. They all find themselves at the Morton Mansion where every year someone mysteriously disappears never to be seen again. Now the brothers must protect the Ghostfacers and defeat the ghost.
Sam and Dean take on a being that uses phones and computers to cause people to commit suicide so it can claim their souls.
The guys go after a doctor who has discovered the secret of maintaining his life as long as he takes other people's organ. Meanwhile, Dean goes to confront Bela and recover the Colt.
It's 30 hours before Dean's deal with the crossroads demon is up and Dean, Sam and Bobby are searching for Lilith, who holds the contract. They discover her location and Sam summons Ruby for help despite Dean's protests. Ruby warns them they aren't ready to fight Lilith yet but they steal her knife and depart for New Harmony, Indiana. In a battle to the death, Sam, Dean and Bobby take on Lilith and all her demons in a last ditch effort to save Dean's life.
Four months have passed and Dean awakes to find himself in a pine box -- he's been freed from Hell. He reunites with Sam and Bobby, but soon they all begin to wonder what pulled Dean out of Hell.
Sam and Dean are thrown off guard when the spirits of Meg and Agent Henricksen accuse the brothers of failing them. Though stunned, the brothers must help Bobby, who is devastated after fighting angry ghosts of children he couldn't save.
Dean is shocked to discover he has been transported back in time to Lawrence, Kansas. But the shock is short-lived after running into a younger John Winchester and Mary who are in love.
Dean is unaware why he was sent back but is enjoying his time with his parents and new-found grandfather, who may be the key to Sam and Dean's predicament.
Sam and Dean learn Jack Montgomery is transforming into Rugaru, a flesh-eating monster. People infected are unaware as to what is going on until they turn into cannibals and begin to eat human beings. Sam tries to reason with Jack so that he will control his urges, but Dean refuses to believe that the urges can be subdued.
Sam and Dean look into a string of murders committed at Oktoberfest. The first victim is found with bite marks, leading them to believe they were caused by a vampire. However, the second victim appears to be killed by a werewolf. When a mummy rises from the crypt, Dean believes that a shape-shifting creature is behind the attacks.
Dean becomes the latest victim of a ghost sickness that causes the victims to steadily become more fearful until their hearts burst. With time running out, the brothers must figure out how to destroy the ghost responsible.
With Halloween quickly approaching, Sam and Dean must find a witch who is making human sacrifices in order to summon a demon. Meanwhile, Castiel returns with Uriel, an angel wanting to smite the entire town.
In a small town, a young girl's teddy bear comes to life. Sam and Dean discover that the town's wishing well really works, blurring the line between reality and fantasy.
Sam and Dean must team up with Ruby to find Anna, a girl who can listen in on angelic conversations... and who the demons want to acquire. Meanwhile, Sam fills Dean in on how he met Ruby during Dean's time in Hell.
While Castiel and Uriel seek out Anna, who can overhear angelic conversations, the Winchesters hide her from Heaven and Hell alike and discover the origins of her powers.
When the ghost of a young woman haunts an abandoned house, Sam and Dean investigate. However, the situation gets complicated when a family moves in and ignores the brothers' warnings.
The brothers investigate a magician's convention where the participants are dying off-stage from illusions that an older magician, The Incredible Jay, is performing on-stage.
Sam and Dean find out that a spirit is haunting one of their old schools. Through flashbacks we see what school was like for the Winchesters
Sam and Dean investigate murders in a small town and fall under the sway of the Siren responsible.
Dean and Sam investigate a town where no one can die... ever. Meanwhile, Alastair prepares for his next move against the forces of Heaven.
Castiel and Uriel recruit Dean to use the torture skills he honed in Hell to interrogate Alastair, who they believe knows which demon is responsible for the murder of seven angels.
Sam and Dean both work at a ironworks company. Dean is in sales and marketing, Sam in tech support. They don't remember each other, or their lives as Hunters. However, when a ghost starts causing suicides among the employees, the brothers have to learn quickly who and what they are, or die trying.
Dean and Sam learn that they're the protagonists in a series of cult novels detailing the adventures of two intrepid supernatural hunters. They confront the author, only to discover that he's the prophet of the Lord... and he's writing the Winchester Gospels. Now Sam must deal with the writer's next prophecy: that he gives in to Lilith.
The guys are on the road when a call comes in on their dad's old cell phone. A college student named Adam Milligan says that his mother's disappeared and he's trying to get hold of his father: John Winchester.
Dean gets a message to meet with Castiel on important business, but he and Sam discover that Castiel has been recalled to Heaven and his human host body, Jimmy Novaks, has no memory of what happened or what Castiel knew. Unfortunately, the demon forces don't know that, and wouldn't care if they did, and will go to any lengths to get Jimmy for themselves.
Sam is plagued by horrendous nightmares and visions from his past as Bobby and Dean force him to go cold turkey to break his addiction to demon blood. Meanwhile, Castiel makes Dean a deal, and the demons break all but the last few Seals.
On the eve of the Apocalypse, Lilith plans to open the last seal and Dean and Sam find themselves on opposing sides. Zachariah reveals Heaven's intentions and Castiel must make a choice. And the nature of the last seal is revealed.
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.
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.
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.
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.
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.
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.
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.
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.
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.
With Sam inescapably trapped in Hell, Dean has no choice but to settle into a normal life with his girlfriend, Lisa Braeden. However, when supernatural occurrences begin in his neighborhood, Dean has no choice but to investigate... and discovers Sam is alive and well, and has brought family with him.
Sam turns to Dean for help when he's forced to take in the baby of parents murdered by shapeshifters. However, the brothers realize they have more problems when they discover that the baby is a shapeshifter... and its father will stop at nothing to recover it.
When three policemen are struck down by the plagues of Moses, the brothers investigate and call upon Castiel. He reluctantly appears to explain that the murders are caused by the Staff of Moses, and that there's a civil war in Heaven.
It's several days in the life of Bobby Singer, when he tries to recover his soul from the demon Crowley, deal with Sam and Dean's personal issues, cope with an outbreak of international monsters, handle a local woman with a crush, and get a piece of peach cobbler.
While investigating a series of murders caused by vampires, one of them feeds Dean his blood. While Dean tries to fight off the compulsion to feed on humans, Samuel arrives with a cure... but it will require the blood of the vampire that converted him.
When several people kill themselves after asking for the truth, Sam and Dean investigate and realize that Veritas, an ancient goddess of truth, has been summoned. Her victims die when they hear more truth than they can stand. However, when Dean is cursed, he decides to take advantage of the situation to ask Sam a few questions.
Castiel confirms what has happened to Sam, and the brothers go to Samuel for answers. He's busy leading a hunt against the Alpha Vampire, and the Winchesters insist on going. However, the hunt goes horribly awry, and Dean and Sam learn what Samuel is up to.
Crowley forces Dean and Sam to bring him an alpha monster. They go after a skinwalker, who plans to infiltrate his people into homes disguised as dogs and then have them all bite and transform their owners, creating a growing army. Meanwhile, Dean deals with the differences in Sam.
The brothers investigate a series of abductions attributed to aliens. However, when Dean disappears and then reappears, they realize that the culprits are fairies, and only someone taken to the fairy realm can see them.
Meg kidnaps the Winchesters, who offer her a deal: they'll help her destroy Crowley, the new lord of Hell. In return, she'll torture Crowley for the information on Sam's soul. The brothers turn to Castiel and Samuel for help, but neither one is enthused at the plan.a
Dean decides to bargain with Death to get Sam's soul back, and has to accept a wager. Meanwhile, Sam refuses to take the risk of getting his damaged soul back, and prepares to cast a spell to prevent Dean's efforts... a spell that requires the blood of someone who has been like a father to him.
Sam emerges from his coma and discovers that he remembers nothing since losing his soul. Dean and Bobby try to keep the secret, and the brothers head to Oregon to investigate the disappearance of several local female virgins. However, they soon discover that something far more sinister is involved.
Sam is lured back to a Rhode Island town where he and Samuel handled a case a year ago... and the monster is still at large, seeking revenge.
The brothers investigate two murders that appear to have been committed by haunted mannequins. As they try to save a third potential victim, Ben calls Dean and says that they have an emergency at home and Lisa is in danger. Dean takes off, leaving Sam to discover the ghost's identity.
To protect them from a killer angel, Balthazar sends Sam and Dean to an alternate dimension where they are duplicates of "Jared Padalecki" and "Jensen Ackles," actors who appear in a show about two brothers who hunt monsters. The brothers are forced to pretend to be actors, but soon discover that the angel has followed them.
Eve, the Mother of All, unleashes a new monster upon the world: a black worm-slug that can enter the brain and force people to kill. Sam and Dean join forces with Bobby and Rufus and track it to a cannery, only to discover that Gwen and Samuel are also there looking for the monster... and none of them know who the monster is inside.
Sam, Dean, and Bobby find themselves in a reality where the Titanic never sank, and 50,000 people are in the world who weren't before. However, in the new reality someone is now killing those 50,000 people one at a time... while Bobby is married to Ellen Harvelle,
Dean and Sam learn that Eve can be destroyed by the "ashes of the phoenix," but the only recorded instance of such a monster is in 1861, when it was killed by Samuel Colt. The brothers convince Castiel to transport them into the past to recover the ashes, but the angel can only give them 24 hours. However, when Castiel is injured by one of his fellow angels, he must turn to Bobby for help to bring the brothers back.
After recovering the phoenix ashes, the brothers, Bobby, and Castiel seek out Eve. They find her in a small Oregon town, where a mysterious plague of shapeshifting is taking place and the quartet soon find themselves surrounded by enemies.
Castiel contemplates his long existence and recent events, while the Winchesters and Bobby begin to realize that the angel is hiding something from them.
Crowley abducts Ben and Lisa to force Sam and Dean to stop hunting him, but Dean refuses to back down. Meanwhile, Bobby tracks down the survivor of a party hosted by H.P.Lovecraft in 1937 and discovers that someone close to him isn't who he believed them to be.
Castiel removes Sam's memory block as a diversion to keep Dean busy, while the angel continues with his plan to become the new God. While Dean wonders what to do, Sam confronts the broken fragments of his own psyche, while Crowley is forced to find a new partner.
Dean, Sam, and Bobby must come to grips with Castiel, who now has the powers of God and sets off to redress the wrongs of the entire world. To defeat God, they must summon Death. Meanwhile, Sam tries to deal with his memories of Hell after the block in his mind cracks.
The Leviathans begin their plans to consume everyone who dwells on Earth. While Dean and Bobby try to track them down, Sam is still haunted by Lucifer, who only he can see or hear.
After escaping the Leviathans in Sioux Falls, the brothers hole up in Montana to heal their injuries. However, Sam reads about a local case of an icepick killer and takes off on his own to deal with it despite his recent mental issues.
Two men turn up dead, killed in a manner similar to crimes that they committed in the past. When the brothers investigate, they discover that the Egyptian god Osiris is judging people and weighing they're guilt... and if they are guilty, they meet a final, permanent justice. Osiris decides that his next target will be Dean.
Sam and Dean investigate three bizarre deaths in the same town and learn that the victims are all tied to a real estate developer, Don Stark. They soon realize that Don's wife, Maggie, is a witch and has learned that he had an affair and is striking down anyone close to him.
The Leviathans put a new plan into motion, having two of their own duplicate the Winchesters and go on a killing spree. While the brothers go out to dispose of their counterparts, Bobby interrogates their captive Leviathan and gets an unexpected visitor.
Despite their recent separation, Sam and Dean are forced to work together when they both end up in Lily Dale, the most psychic town in America, to investigate the bizarre deaths of two mediums.
During the brothers' annual pilgrimage to Las Vegas, Sam makes a life-shattering decision and takes on a new partner. Dean soon finds a new hunter as a partner, but the Winchesters meet again when they end up investigating the same case.
Dean, Sam, and Bobby investigate mysterious disappearances in New Jersey, attributed to the "Jersey Devil," but soon discover that the Leviathans are responsible and have a plan to conquer the country through the miracle of mass-marketing and fast food.
While Sam and Dean watch over a dying friend, Bobby teams up with Rufus to stop a Reaper.
While Dean tries to find Dick Roman, Sam looks into the disappearance of a hunter at a truck stop and teams up with the man's daughter to figure out what happened to her father.
When the brothers investigate the mummification deaths of two individuals in Canton, Ohio, they soon discover that they're up against a god... and Dean ends up transported to 1944 with no way back.
While the Winchesters investigate a string of brutal serial killings, Dean decides to go to a bar and pick up a woman. They end up having sex, but Dean soon discovers that his one-night stand is anything but.
Sam and Dean investigate a case in Wichita involving a man who was killed by an octopus on dry land. They soon discover that childhood fears are coming to life, and that a children's pizza place is the center of the phenomena.
Sam and Dean return to the town where they tortured a demon for information four years earlier and then exorcised it. Now the demon is apparently back and taking up its old trade: killing woman. Meanwhile, Sam tries to cope with his visions of Lucifer.
The brothers investigate several cases of cursed antiques turning up in Portland, but soon discover something far more sinister when they learn that the Leviathans are buying up real estate in the area. Meanwhile, Sam is still plagued by Lucifer's voice in his head.
When Sam's worsening mental condition puts him into a psych hospital, Dean goes looking or a healer and finds one man seemingly blessed of God: a man who bears a striking resemblance to Castiel.
Dean's one-time hunting partner, Garth, calls him in when he runs up against an invisible monster that disembowels its victims. Garth and the Winchesters soon discover that someone has invoked a shojo, an alcohol spirit that someone can only see when they're drunk. Meanwhile, the Winchesters consider the possibility that Bobby's spirit is trying to contact them.
A hunter, Annie Hawkins, misses a meeting with the Winchesters. They discover that she was last seen at a famous haunted house and go to investigate... unaware that Bobby is with them as a ghost.
Dick Roman orders one of his computer programmers to hack Frank's computer drive and find out the information on the Winchesters' new identities. She goes along but soon finds out everything Frank knew about the Leviathans, and Dean and Sam recruit her to go after Dick and find out what he has planned.
When Dean and Sam open the clay tablet, an unsuspecting high school student becomes involved in the war against the Leviathans. Meanwhile, Meg calls the Winchesters with news about Castiel.
Dean and Sam must try to gain the two remaining components necessary to defeat Dick Roman: the blood of the Alpha Vampire and Crowley. Meanwhile, the Winchesters must also deal with Bobby, who is slowly giving into his rage and threatens to go out of control.
As Dick Roman prepares to make his move and turn the U.S. into a slaughterhouse, Sam and Dean attempt to assemble the weapon necessary to stop him. However, when Castiel refuses to fight, the Prophet Kevin is captured, Crowley joins the other side, and Bobby goes berserk, everything looks hopeless for the Winchesters.
Dean and an unlikely ally escape from Purgatory. However, Dean soon discovers that Sam has retired as a hunter. When they learn that the Prophet Kevin has escaped his captivity, the Winchesters go back to work to save him and discover that he holds the key to defeating every demon on Earth.
Kevin insists that the Winchesters take him to check on his mother Linda and they discover that she's being watched by demons. Once they free Linda, she insists on going with them to protect her son as they recover the tablet.
Dean and a reluctant Sam investigate two bizarre murders in two different cities where the victims' hearts were ripped off. The brothers catch up to the killer but discover that he is in a trance and mumbling words in an ancient language.. and couldn't have been at one of the murders.
While searching for a werewolf killer, Sam and Dean find some video footage of three students who encountered the werewolf... and one of them were bitten and infected.
When Benny gets injured hunting down his Maker, he calls on Dean for help. Dean abruptly leaves Sam in the lurch, saying he has personal business. While he waits, Sam remembers how he and Amelia bonded.
While investigating a spectre that possesses individuals and brings out their inner rage, Sam and Dean run into Garth, who is taking Bobby's place.
While the brothers investigate a series of strange disappearances, they're startled when Castiel appears out of nowhere with no memory of how he escaped Purgatory. Meanwhile, the Trans consult with a witch in an attempt to create weapons capable of destroying Crowley and his minions.
Rather than go to Heaven, Castiel chooses to join Sam and Dean as a hunter. On their first case, they investigate a series of strange deaths that seem based on cartoon reality.
Sam has family friend and fellow hunter Martin Creaser take on the easy job of watching over Benny, Dean's vampire ally. However, when a corpse turns up drained of blood, Martin calls Sam in and Dean insists on making sure that Benny is truly guilty before they kill his friend.
While Sam and Amelia decide what to do with their relationship, Castiel comes to Dean and asks for help rescuing an angel being tortured by Crowley.
When a killer literally goes medieval on two live-action roleplayers, Dean and Sam check out a local gathering and discover that their friend Charlie Bradbury is the queen of the kingdom... and her subjects are under attack.
Henry Winchester, Sam and Dean's grandfather, travels through time to the present to escape a demon seeking a box that he has taken. As Henry tries to find a way back while dealing with the demon, he tells the brothers about their true heritage.
While investigating the Men of Letters, Sam and Dean find the group's secret headquarters. As they set up shop, the brothers discover that a rabbi, Isaac Bass, spontaneously combusted and had ties to the Judah Initiative, a secret group that fought Nazi necromancers during World War II. When the brothers investigate, they meet Isaac's grandson Aaron... and the clay golem that Isaac gifted to him.
When Kevin discovers that someone must complete three trials of God to seal the gates of Hell, Sam and Dean set out to kill a hellhound for the first trial. They soon discover an entire family that may have made a crossroad deal... and the brothers have to decide which of them will take the first trial.
James Frampton, a police officer who worked with the Winchesters on a previous hunt, calls them for their help. he has learned witchcraft since they last met, and is now having nightmares of savage murders... that happen in real life.
When Sam and Dean encounter a man who dies and keeps coming back to life, they soon discover that he's the Greek Titan, Prometheus. They also discover that Zeus' daughter Artemis wants Prometheus dead for good.
Castiel returns to help the Winchesters when they become involved with Crowley's hunt for Lucifer's Crypt. The trio soon finds the source of Crowley's information: Meg, tortured for her knowledge of the Crypt's location. As they race to find the Crypt before Crowley, the Winchesters soon realize that Castiel is hiding important information from them.
While on the trail of a vampire nest, Sam and Dean run into three teenagers who are hunters in training. One of them is Krissy, who Dean helped out on a previous case. The Winchesters check out the teenagers' home life and discovers that a Hunter is raising them to be the next generation of hunters.
Kevin discovers that Crowley has found a way to make mental contact with him, and calls the Winchesters. When they arrive, Kevin tells them that he's found out the second trial. To succeed, Sam must travel to Hell, rescue an innocent soul, and bring it to Heaven. With the help of a Reaper, Sam gets to Hell and discovers that he must rescue an old friend. Meanwhile, Dean must turn to another old friend to rescue Sam when his escape route is cut off.
Charlie calls in Dean and Sam on a case of corpses with liquified organs, but they soon discover that she has an ulterior motive. Meanwhile, Sam continues to weaken after completing the second trial.
After receiving Kevin's files, the Winchesters get a lead that takes them to a Colorado town that no one seems to visit. Meanwhile, Castiel attempts to stay ahead of Naomi and her hunter-angels, and Crowley tries to trick Kevin into revealing the Winchesters' plans.
Sam and Dean try to figure out how to fulfill the third trial--cure a demon--and Dean refuses to have Castiel help them after the angel's recent betrayal. Meanwhile, Crowley launches a new plan to force the Winchesters to turn over the tablet, and Metatron devices a scheme to stop the angel war from spreading out onto Earth.
Sam and Dean are forced to negotiate with Crowley, but they use the opportunity to capture the demon so they can complete the third trial. Meanwhile, Naomi discovers that the trials that Metatron have given Castiel to complete don't accomplish what the Scribe of God claims, and tries to warn Castiel of the truth before it's too late.
While Sam hangs on the edge of life and death, Dean appeals to the fallen angels for help. Unfortunately, most of them only see Dean as a means to get to Castiel and exact bloody vengeance on the one who caused them to Fall. Meanwhile, Sam wrestles with his inner demons and Castiel learns what it means to be human.
Dean and Sam take a captive Crowley to the Men of Letters base in the hopes that he will give up the names and host bodies of his minion demons. However, they are called away to investigate the disappearance of three soldiers, which leads them to Abaddon, the Knight of Hell... and forces Ezekiel to take control of Sam's body to save his life.
Castiel makes his way to the Winchesters but discovers a band of angels are hunting him, intent on making him pay for what they believe is his role in banishing them from Heaven. Meanwhile, Ezekiel continues to repair Sam's price, but informs Dean that there is a cost to be paid.
With some help from Charlie, Sam and Dean inadvertently release two individuals contained inside of the Men of Letters bunker: an evil witch, and a young woman, both imprisoned since 1935. They soon discover that the woman is Dorothy of Oz, and she is hot on the trail of the Wicked Witch, who plans to summon her evil army to Earth and conquer the planet.
To track down a killer, Dean uses a spell to talk to a German Sheppard that was at both murders. However, he soon discovers that everything is going to the dogs when the spell starts making him act like a canine as well.
Castiel is working as a convenience store clerk and learns of a series of local disappearances. He call the Winchesters, but Dean insists on Sam staying with Kevin to research the Tablet while he investigates.
Sonny, a man who runs a boy's home, calls Dean in after a mysterious death occurs. When Sam wonders how his brother knows Sonny, Dean explains that he spent two months there when he was 16 after being arrested for theft.
When a mysterious abductor targets members of a virgin chastity group, Sam and Dean go undercover to track down the killer when Sheriff Jody Mills asks them for help. However, Dean disappears and Sam and Jody end up tracking him down.
The angels fight each other in bloody civil war, and Castiel is swept up in the conflict. Meanwhile, Dean realizes that Ezekiel is not who he claims to be and tries to warn Sam with dire results.