Having a childhood that taught them to hunt things that go bump in the night, Sam and Dean Winchester embark on a trip to find their missing father, who vanished while searching for the demon that killed their mother.
Reeling from Jessica's death, Sam accompanies Dean to Blackwater Ridge based on clues from their father's journal. Once there, they help two siblings find their missing brother who was taken by a mysterious creature.
The brothers investigate a series of drownings that reveal the presence of a vengeful spirit with a personal vendetta.
An old acquaintance points the brother to a case involving a mysterious plane crash, and a demonic entity that is methodically eliminating the remaining survivors.
A ghost inhabiting a mirror is summoned by chanting of the name Bloody Mary. As it works to kill guilt-ridden individuals, Sam and Dean race to put an end to the bloodshed.
Sam fights to prove the innocence of one of his friends after a shapeshifter impersonates him and implicates him in a murder.
A series of murders point to the culprit being a figure from an urban legend, being accidentally controlled by an unsuspecting college student.
In Oklahoma, the brothers' latest case reveals a desecrated burial ground and a powerful curse that unleashes swarms of deadly bugs.
In the wake of a disturbing nightmare, Sam and Dean return to their old family home to help the current residents, confronting their painful past as familiar faces show up to help.
Following a tip from their father, Sam and Dean head to a haunted asylum, where they discover that the spirits are actually the benevolent victims of a sadistic doctor.
John's call leaves Sam and Dean at odds. While Sam makes the attempt to join their father's search for their mother's killer, Dean decides to follow John's advice and investigate a series of disappearances.
As Dean's life hangs in the balance, a desperate Sam enlists the help of a preacher capable of performing miracles, only for the brothers to learn of the disturbing secret behind those so-called miracles.
Dean has to deal with his reawakened feelings for a former girlfriend as she enlists his help to solve her father's murder, a case that turns out to involve a racist truck.
As Sam and Dean come to realize that Sam possesses special powers, Sam's vision leads them to a case that reveals an unexpected connection to their own past and Sam's powers.
When Sam disappears during a case, Dean teams up with the local sheriff to find his brother. Their investigation proves that humans can be just as evil and cruel as supernatural creatures.
When their latest case leads them to a familiar face, Sam learns the disturbing truth about Meg and her plans to use him and Dean against their father.
The brothers have to put up with local paranormal investigators who turn out to have an accidental connection to the revival of a figure from an urban legend.
Sam and Dean revisit the past when their father sends them to find closure for an old case that was left open after Dean made a terrible mistake that put Sam's life in danger.
Sam and Dean investigate a murder that reveals a history of blood and mayhem with one common factor: all the victims owned the same painting.
The hunt for the killer of John's old mentor reveals a powerful weapon that could give the Winchesters a shot at getting revenge for Mary.
Meg goes on a murder spree in an attempt to retrieve the Colt. Sam and Dean try to get ahead of Azazel's impending attack on another family.
As they gear up for a confrontation with Azazel, Sam and Dean turn to their old friend Bobby Singer for help. Azazel's planned trap proves to be no match for John's fatherly love for his sons.