One of the Winchester men hovers between life and death as his family faces an old and powerful adversary.
A cell phone message leads Sam and Dean to a woman named Ellen, whose home serves as a gathering place for other hunters; a small-town carnival serves as a cover for a murderous clown who preys on parents.
Sam and Dean meet a fellow demon hunter (Sterling K. Brown), who systematically kills vampires in a small town.
Dean and Sam investigate a college student's (Summer Glau) murder; the ghost has risen from the dead seeking revenge on those who mistreated her when she was alive.
Sam and Dean meet Andy (Gabriel Tigerman), a slacker with psychic powers of persuasion; when Andy's friends start dying the brothers question if Andy is using his powers to kill.
Sam and Dean investigate the brutal murders of blond women from an apartment building and discover the demon responsible is the ghost of the first serial murderer.
Sam and Dean investigate the murders of a lawyer and his wife who claimed to see a ghost before they died; local detectives arrest Sam and Dean for double murder before they are able to find the ghost.
Sam and Dean investigate a local dive bar and discover it is on a site where a deal-making demon has been making people's dreams come true in exchange for their souls.
Sam has a vision of Dean killing a young man who seems to be possessed by a demon, leading the brothers to head to Oregon in search of answers; Dean reveals what John whispered to him before dying.
Distraught Sam sneaks off to Indiana without Dean after Dean tells him what their father said before he died; a psychic tells Sam that she sought him out to warn him of his impending death.
Sam and Dean investigate two deaths at a small Connecticut inn run by a single mom whose young daughter plays with an imaginary friend.
Sam and Dean investigate robberies in which trusted employees hold up banks then commit suicide, but autopsy results indicate the actual times of death as being several days before the robberies.
Sam and Dean investigate the murders of several people by individuals who claim they were visited by an angel and carrying out God's will.
Dean races to Sam's side after receiving a frantic call from him; the brothers discover a tape that shows Sam killing another hunter.
Sam and Dean call upon a family friend (Jim Beaver) for help when unexplainable happenings at a local college stump them.
Sam and Dean help a young woman (Tricia Helfer) they meet on a dark highway, where a phantom farmer is chasing her.
Sam and Dean investigate the death of a lawyer who appears to have been killed by a wild animal.
Sam and Dean investigate the death of an actor on a horror-film set after rumors indicate that he was killed by a ghost.
Sam and Dean get themselves thrown into the state penitentiary when they hear about a ghost that has been killing inmates.
After being attacked, Dean visits a world where he lives a normal life with his girlfriend, his mother is alive, and Sam is engaged to Jessica (Adrianne Palicki).
Abducted by the Yellow-Eyed Demon, Sam finds himself in a ghost town with others who have special abilities and learns they are to be soldiers in a war against the human race.