Sam and Dean investigate a series of mysterious drownings written off as suicides. They discover the spirit is an angry little boy with the power to travel through water who is taking revenge on certain town inhabitants for a dark secret buried long ago. Dean forms a bond with a young boy who seems to have the power of premonition.

While battling a demon, Dean is electrocuted, resulting in permanent damage to his heart and leaving him with only a couple of months to live. A despondent Sam searches desperately for a way to save his brother and believes he may have found an answer through a preacher who claims to heal the incurable. However, Dean and Sam discover that the preacher is getting help from the Grim Reaper who is trading one life for another he feels is less worthy.

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.

John has realized where the demon will strike next and the Winchesters head there to stop the next killing. But Meg begins killing John's friends and demands the Colt or she'll keep going until everyone John knows is dead.

Sam and Dean encounter a vampire hunter whose obsession may get them all killed.

Dean calls a demon to make a deal to save a man named Evan Hudson, in exchange for himself. While making the deal, the demon confronts Dean’s worst nightmare about their dad.

An angel causes people to cheerfully go out to murder, and when the Winchesters investigate one of them falls under its sway.

Sam and Dean investigate a brutal death and discover that the killer is a lycanthrope: a werewolf.

Sam and other "special children" are abducted by the Yellow-Eyed Demon and taken to a ghost town, where the ultimate battle must start.

Sam & Dean track down changelings that are pursuing mothers and their children. A boy they protect bears a strange resemblance to Dean, which at first makes Dean uncomfortable because he once had a one-night stand with the boy's mother Lisa.

The brothers capture a female vampire named Lucy who has no idea how she became one, which leads them to Dixon, a male vampire who is a little too giving. Gordon returns with a vengeance leaving Sam in danger.

FBI Agent Henricksen finally captures Sam and Dean, but is caught in the middle when a horde of demons descends on the small-town jail to eliminate the brothers.

Sam and Dean search for a Crocotta that uses the phone and computer as a means to communicate with people. Its goal is to get people to commit suicide and take their soul. Dean gets some news from an unlikely source about a demon holding the contract to his soul.

Sam and Dean discover a doctor who, back in 1816, became obsessed with finding the secret of eternal life by taking people's vital organs. Meanwhile, Bobby finds Bela and Dean leaves Sam to confront her.

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.

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?

Dean and Bobby have something frightening locked in Bobby's panic room: Sam, contaminated by demon blood. But as the apocalypse draws nearer, Bobby wants to free Sam to battle on their side.

Hunter Rufus Turner calls in Bobby, Sam, and Dean to deal with a demon infestation in his town, but they soon discover the truth is much more horrifying. Meanwhile, Castiel goes to seek the only entity that can defeat Lucifer.

The angels send Anna back in time to kill John and Mary Winchester before they can conceive Sam knowing that if Sam was never born then Lucifer won't be able to use him as his vessel. Castiel sends Sam and Dean back to 1978 so they can stop Anna, and the two brothers are reunited with their parents. Mary recognizes Dean as a hunter since he visited her in the past once before but tries to keep the truth from John.

Crowley tells Bobby he will give him the location of Death, the fourth horseman, in exchange for his soul. Knowing Sam and Dean need that fourth ring to stop the Apocalypse, Bobby reluctantly agrees. Sam and Dean confront Pestilence, but he unleashes a deadly virus upon them, so Castiel must intervene on their behalf. Dean has a meeting with Death to discuss Lucifer, and an unholy alliance is formed at a very high price for Dean.

Sam is mysteriously released from Hell and seeks out his brother, trying to have a normal life. Together the brothers must join forces with their maternal grandfather, Samuel, and begin the fight anew.

Dean seeks out Death to help get Sam's soul back. Death tells Dean he will help Sam if Dean will agree to act as Death for 24 hours. Meanwhile, Sam decides he doesn't want his soul back and asks Balthazar for a protective spell to keep his soul out of his body. Balthazar tells Sam he needs the blood of his father for the spell to work and since John Winchester is dead, Sam decides Bobby is the next best thing.

A demon kidnaps Ben and Lisa to get to Dean. Sam and Dean are forced to join with an unlikely ally to free them.

Castiel doesn't kill Sam, Dean and Bobby but warns them not to interfere in his business. Assuming his new role as God, Castiel sets out to right some of the wrongs in the world. Dean decides they should bind Death and order him to stop Castiel, but the former angel is one step ahead of them, leaving Dean to face a very angry Death. Meanwhile Sam struggles to deal with the broken wall in his head.

As Sam and Dean race the clock on a high-stakes mission, Bobby seeks the help of an unlikely old friend to solve one of the most personal cases of his life.

Lucifer drives Sam to the breaking point and Sam ends up in a mental hospital. Desperate to save his brother, Dean calls every hunter he knows for help. One of the hunters gives him the name of a healer who turns out to have a very familiar face.

Dean and Sam prepare for battle with Dick Roman. Dick's in the final phase of his plan and the Winchesters must team up with Castiel, Bobby, Meg and Kevin, the prophet, to stop him. However, Dick is one of the smartest enemies they've ever faced so it's a mind game to see who can keep the upper hand.