Sam and Dean Winchester were trained by their father to hunt the creatures of the supernatural. Now, their father has mysteriously disappeared while hunting the demon that killed their mother, 22 years ago.
Sam and Dean are called in to investigate when a plane crashes under mysterious circumstances. Their investigation leads them to the conclusion that a demon is possessing people and causing them to crash the plane they are on. Things become more urgent when they discover that the demon is going after the 7 survivors of the crash, including the pilot and a stewardess.
All over the world, kids play the "Bloody Mary" game, daring each other to say her name three times in a mirror. But no one has even died from it. Until now. Sam and Dean must find a way to stop her before she claims another victim.
When one of Sam's old school friends is framed for the murder of his girlfriend, Sam and Dean investigate, discovering that a shapeshifter is responsible for that murder and possibly other similar murders.
Sam and Dean help a girl whose date became a victim of the "Hook Man," a famous urban legend that turns out to be real, in a small college town somewhere in Iowa. In order to save her and her father, the local minister, the brothers have to find the ghost's bones so they can destroy them. But Sam and Dean run into a problem when they discover that the bones are in an unmarked grave.
Following visionary Sam's recent nightmare about the former Winchester home in Lawrence, Kansas, where the present dwellers, Jenny from Wichita and daughter to two small kids, are suspiciously accident-prone, Dean reluctantly accepts to drive there. Dean and Sam reassure Jenny but follow up on the kids fear of a flaming creature in the closet. They consult Missouri Moseley, their father John's old medium friend, and together with the spirit of Mary Winchester, confront an evil poltergeist, but a second ghost intervenes and someone hides behind Missouri.
Sam and Dean investigate an abandoned sanitarium and discover that when the hospital was open, the patients held a revolt against the cruel and unusual experimental treatments carried out by the head doctor. Now the ghosts roam the halls, driving anyone who spends the night insane. While trying to rescue two lost teenagers, Sam is captured and turns against Dean.
While in a motel, Sam and Dean receive a call from their father, asking them to give up trying to find him and to take note of the names of three young couples that had disappeared in Indiana along the last three years, always on the second week of April. Sam decides to go after his father in California and leaves Dean, who arrives in the small town of Burkitsville for investigation of the missing couples. Sam meets the drifter Meg, who is also hitchhiking to California on the road, and stays with her waiting for a bus in the bus station. Dean discloses that a pagan ...
When Dean is accidentally electrocuted fighting a monster, he permanently damages his heart. When he's diagnosed as only having a month, at most, to live, Sam searches for a means to save him and finds Roy Le Grange, a faith healer who may actually be the real deal. After Le Grange heals Dean, the brothers discover that Le Grange is using black magic to bind a "Reaper" to do his bidding... and each healing comes with a terrible price of someone else's life.
Sam has a premonition in which a man is killed, but the murder is made to look like a suicide. Sam convinces Dean that they must investigate the case, but the two are puzzled when they fail to find anything that indicates that the death was supernatural in nature. That is, until they find out that Max, the reclusive son of the first victim, has been using his recently acquired power of telekinesis to kill the family members that once abused him. Sam also discovers Max's mother was killed by the same fiery demon that took his own mom.
After hearing in 'smallville' Hibbing, while masquerading as Minnesota state police, a boy's story about a monster probably was inspired by a Godzilla movie, Sam points out the county was marked by dad as suspicious and has the state's highest ratio of disappearances, but Dean just wants to relax, at least till the morning, until Sam disappears on the parking lot. Dean teams up with local police woman Kathleen, who even after finding out they impersonated cops decides not to arrest him before Sam is found, because her own brother also disappeared years earlier. Their ...
Dean and Sam are investigating a mysterious murder in Chicago and discover that Meg is responsible for it. However, when they try to catch her, Meg unleashes shadow spirits on them and they realize that she is really setting a trap for their father.
Sam and Dean investigate the case of a maniacal ghost inhabiting a long abandoned Texas farmhouse known as "Hell House." They believe the ghost is the spirit of a deceased Depression-era farmer who killed his family, but they soon realize it is something far more powerful.
Sam and Dean investigate a small town in Wisconsin where children are falling into comas for no apparent reason. The brothers discover that a witch is creeping into the bedrooms of the children and stealing their "life force." While battling the witch, Dean recalls a past mistake that almost cost Sam his life at the hands of the very same witch, an event which has fueled Dean's protectiveness over Sam and his blind obedience to his father.
A young couple is murdered in their home shortly after buying an antique painting of a family portrait circa 1910. Upon reviewing the painting's provenance, Sam and Dean learn that everyone who has ever bought the painting has been murdered and race to discover how the portrait is causing the deaths before it can claim its next victim.
After Daniel Elkins, a vampire hunter and John's mentor, is murdered, Sam and Dean are surprised when John himself shows up to solve the case. John discovers the vampires have taken an antique gun, which has the power to kill all supernatural beings. The Winchester family sets out to retrieve the gun from the vampires so they can use it to kill the demon that took Sam and Dean's mother.
Meg turns to killing John's friends in order to get the Colt. Sam and Dean stakeout the Demon's next target; a family with a six month old baby showing signs of special abilities. John heads off alone to confront Meg.