Hell beckons again when Dean is stricken with a mysterious illness that frightens its sufferers to death. Sam and Dean scramble to find the cause of the disease in time to save Dean from sure death.

Fast times at Truman High. Murder brings Sam and Dean back to one of their old high schools, where they investigate possible demonic possession and take a few trips down memory lane.

Meet the Winchester boys: Dean, Sam and... Adam. The Winchesters discover they have a younger half-brother, whose mother vanishes just as a long-dormant grave robber renews his ghoulish career.

Sam and Dean investigate a series of odd murders that strangely resemble fairytales and urban legends. The brothers track down an 11-year-old boy named Jesse and realize that whatever Jesse believes is coming true. Castiel tells Sam and Dean that Jesse is a serious threat and needs to be eliminated.

A former hunter named Martin, who is currently institutionalized, calls Sam and Dean for help investigating a case in the mental hospital. The brothers get themselves admitted as patients to check out the mysterious monster that is attacking the patients, but their incarceration pushes both to the breaking point as they unleash their inner demons against each other.

Ambushed by angry hunters, Sam and Dean are shot and killed. When they wake up in heaven, Castiel tells them that they need to find an angel named Joshua, who talks directly with God. But he also has a warning, Zachariah is searching for them.

After Bobby discovers Crowley has no intentions of returning Bobby's soul, the hunter takes matters into his own hands. He calls on Sam and Dean for help after he unearths one of Crowley's deepest secrets. Meanwhile, Sam and Dean learn what Bobby does all day when they are not around.

Dean becomes suspicious of Samuel's motives, but Sam isn't sold on the idea that their grandfather is doing anything wrong. The brothers go along on a hunt with Samuel and the other Campbells, but things go terribly awry.

Sam starts to have flashbacks to a case he worked on with Samuel before he reconnected with Dean. Sam receives a mysterious text with coordinates to a small town, so the brothers decide to investigate. Dean is surprised when the townspeople start telling him some of the things Sam did while he lived there.

Dean is furious after Sam disappears to follow a lead on a case with clues that are identical to a case Sam solved as a kid. The demon turns out to be Amy, who has been killing low-life thugs and taking their brains for dinner - the same demon Sam found as a kid.

While on a hunt, Sam runs into someone from his past and a confrontation ensues. Meanwhile, Dean reluctantly teams up with a quirky, laid-back hunter named Garth, when he finds himself in a situation that he just cannot explain.

Sam and Dean investigate strange happenings in a town where childhood fears are coming to life. To Sam's horror his childhood fear of clowns manifests in a very violent and traumatic way which in turn leads to Dean's childhood fear, losing his brother.

In order to defeat Dick Roman and the Leviathans, Sam and Dean must locate three key items. Castiel gets one of them but for the other two, the Winchesters must face two of their strongest opponents.

Kevin talks Sam and Dean into checking in on his mother. When they arrive, they see that Crowley has surrounded her with demons so they rescue her and take her along on their quest to find the tablet. However, they soon discover Kevin wasn’t kidding when he said his mother was a strong-willed woman after she tries to take on Crowley.

Sam asks a hunter named Martin to keep an eye on Benny without telling Dean. However, when Martin tells Sam and Dean there was a vampire kill and that Benny is responsible, Dean defends his friend.

Sam and Dean are stumped when they investigate a possible zombie case where an amnesiac man dies and then revives himself every day. After the man is attacked by the goddess Artemis, Sam and Dean realize he’s not a zombie.