Bracing themselves for the possibility of an apocalyptic war, Sam and Dean realize they have an enormous task of hunting down the hundreds of demons that escaped from the Devil's Gate.
Dean pressures Sam into visiting Cicero, Indiana so he can visit an old flame named Lisa. However, Dean is stunned when he meets Lisa's 8-year old son Ben, who bears a striking resemblance to him. However, Ben soon goes missing and Sam and Dean discover that a Changling is snatching kids from the small town and assuming their form. Meanwhile, Ruby makes contact with Sam and reveals some startling information about his mom.
Sam and Dean answer a call on their dad's old cell phone, alerting them that someone has broken into John's secret storage room in New York and a cursed rabbit's foot has been stolen.
Sam and Dean investigate a rash of violent deaths in Elizabethville, Ohio, a once-sleepy town that has been turned into a haven for gamblers and drinkers. Dean discovers demons have infiltrated Elizabethville and are using their powers of persuasion to make the townspeople succumb to their basic instincts. Meanwhile, Ruby helps Bobby rebuild the Colt from scratch and stuns him with some news.
A young girl trapped in a coma by her wicked stepmother sets off a series of murders based on the fairy tales read to her by her father. Meanwhile, Sam summons the Crossroad Demon and threatens to kill her with the newly rebuilt Colt unless she releases Dean from his deal. When the demon says it's her boss who wants Dean's soul and it's out her hands, Sam shoots her anyway.
Sam and Dean investigate the mysterious demise of drowned victims who were nowhere near the water at the time of their death. The brothers learn that each of the victims saw a ghost ship shortly before they died. During investigation, they cross paths with Bela, who is being paid handsomely by one of the murder victim's family members to solve the case. Sam and Dean warn her to stay out of their way, but she has other plans.
Sam and Dean capture a female vampire named Lucy who claims to have no knowledge of how she became a vampire. The guys discover Dixon, a male vampire, is giving out human blood to unsuspecting females in bars, offering it up as the "latest drug" and turning them all into vampires.
It's Christmas time and Sam and Dean investigate a series of murders where the victims were pulled up through the chimney. Sam realizes they are dealing with a sort of Anti-Santa, a demon with roots in pagan lore.
Sam and Dean travel to Sturbridge, Massachusetts, and discover a coven of witches that has killed two people. Ruby warns the brothers to stay away as the demon controlling these witches is very powerful and will surely kill them. Ignoring her plea, Sam and Dean go in after the coven and confront the head witch, who reveals Ruby's past.
Sam and Dean race to Bobby's side after he lapses into a coma and can't be awakened. While unconscious, Bobby battles his personal demons and the reason he became a hunter is revealed. Sam and Dean discover someone poisoned Bobby with a potion that will kill him if he doesn't wake soon. When the brothers decide to take the potion themselves to enter Bobby's dream in order to save him, they come face to face with their own personal nightmares.
Sam and Dean investigate the disappearance of a man who went missing at a tourist location. While searching the site, Dean is shot and killed by the owner. Sam is devastated, but stunned when he wakes up the next morning to find Dean alive and well. As the day unfolds, Sam realizes he is re-living the previous day and tries to prevent Dean's death, but to no avail. Dean dies again and Sam must learn to live life without his brother by his side.
Sam and Dean break into Bela's apartment in order to get the Colt back, but she has tipped off Agent Henricksen about their whereabouts and they are arrested.
The Morton Mansion, an abandoned estate becomes one of the most haunted places in America one night each year. However, as the team begins to get picked off in grisly manners not fit for television, they realize they are in over their heads.
Dean is stunned after he receives a phone call from his dad who tells him he has a solution to get Dean out of his deal. Sam and Dean fight because Sam is skeptical that it is really John on the other end of the phone and warns Dean not to listen to him but Dean disagrees and sets off on his own path to follow his father's instructions.
As time runs out for Dean, Sam convinces him to head to Eerie, Pennsylvania to investigate a possible zombie case. Instead, they discover Doc Benton, a real-life doctor who, in 1816, abandoned his medical practice to follow his obsession with finding the key to eternal life by drugging people and stealing their vital organs.
It's 30 hours before Dean's deal with the crossroads demon is up and Dean, Sam and Bobby are searching for Lilith, who holds the contract. They discover her location and Sam summons Ruby for help, despite Dean's protests.