Season 4

After Dean's encounter with Castiel, Dean, Sam and Bobby brush up on their biblical lore when they're attacked by the vengeful spirits of people from the Winchesters' past. They're warned it's a sign that someone is trying to break seals which will bring on the apocalypse.

Back to the future, Castiel sends Dean to 1973 Lawrence, Kansas, where he meets a nice young couple named John and Mary Winchester. Dean's parents. And Mary has a secret.

Dark powers. Dean fears Sam is using his paranormal gifts in conflict with God's plan. And an ordinary guy in an ordinary town gets a major case of the munchies. It starts with steak - and moves to human flesh.

In a black-and-white world reminiscent of classic horror flicks, the brothers tangle with a vampire, a werewolf and a mummy who are thinning the crowds at a quaint Oktoberfest.

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.

Chomping candy, bobbing for apples. Halloween is such fun. Until gruesome deaths signify another seal is being broken. To stop it, Castiel and another angel plan a mass annihilation of the town.

Want to score a hot girlfriend, win the lottery or have your favorite teddy bear come to life? Then plunk a coin in a small town's wishing well and stand back. One problem: The wishes come true with a twist.

What happened to Sam during the months Dean was dead? During the search for a girl named Anna Milton, who has a mysterious connection to angels, Sam reveals the astonishing events of the summer.

The angels want Anna dead, so Sam and Dean go on the run with the frightened girl, determined to discover the secret that has set the furies of Heaven on her.

Dad, Mom, two kids and a dog. An all-American family doesn't stand a ghost of a chance against the bloodthirsty force that turns their new home-sweet-home into a haunted house.

Aging magician The Incredible Jay performs the dangerous Table of Death trick and emerges unscathed. Jay cheated the Grim Reaper, but one of his rivals didn't. He checked out while Jay was doing his act.

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.

In a small town in Iowa, three loving husbands kill their wives. Turns out these guys believe in spreading their love around: Each is spending plenty of the family income on strippers at a nearby nudie bar.

Reapers take a break from work, and that means no one can die. But the escorts to the next world aren't off getting some R&R, unless you call being held hostage by a demon restful and relaxing.

Can torture be God's work? After seven angels are mysteriously murdered, Castiel and Uriel demand that Dean use the agony-inducing skills he learned in Hell to extract information from Alastair.

At Sandover Bridge & Iron Inc., Dean is Dean Smith, the buttoned-down director of Sales & Marketing. Sam is Sam Wesson, a cubicle-dwelling tech support guy. What the heck is going on? Or is it what the Hell?

Familiar plot. Familiar characters. Sam and Dean come across a series of graphic novels called "Supernatural" featuring two demon-hunting brothers named Sam and Dean.

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.

The body Castiel walks around in isn't his. Instead, it belongs to a regular guy named Jimmy who wants his body - and his life - back. He gets the body. But the life may be a different story.

Dean and Bobby have something frightening locked in Bobby's panic room: Sam, who is corrupted by demon blood. With the apocalypse drawing nearer, Bobby wants to free Sam to fight on their side.

The brothers prepare to fight the forces of the apocalypse in different camps. While Sam and Ruby hunt down Lilith, Dean joins Castiel and Zachariah to take on Lucifer.