While Sam hangs on the edge of life and death, Dean appeals to the fallen angels for help. Unfortunately, most of them only see Dean as a means to get to Castiel and exact bloody vengeance on the one who caused them to Fall. Meanwhile, Sam wrestles with his inner demons and Castiel learns what it means to be human.
Dean and Sam take a captive Crowley to the Men of Letters base in the hopes that he will give up the names and host bodies of his minion demons. However, they are called away to investigate the disappearance of three soldiers, which leads them to Abaddon, the Knight of Hell... and forces Ezekiel to take control of Sam's body to save his life.
Castiel makes his way to the Winchesters but discovers a band of angels are hunting him, intent on making him pay for what they believe is his role in banishing them from Heaven. Meanwhile, Ezekiel continues to repair Sam's price, but informs Dean that there is a cost to be paid.
With some help from Charlie, Sam and Dean inadvertently release two individuals contained inside of the Men of Letters bunker: an evil witch, and a young woman, both imprisoned since 1935. They soon discover that the woman is Dorothy of Oz, and she is hot on the trail of the Wicked Witch, who plans to summon her evil army to Earth and conquer the planet.
Songs: AC DC
-- For Those About to Rock We Salute You
To track down a killer, Dean uses a spell to talk to a German Sheppard that was at both murders. However, he soon discovers that everything is going to the dogs when the spell starts making him act like a canine as well.
-- I Want to Know What Love Is
Castiel is working as a convenience store clerk and learns of a series of local disappearances. He call the Winchesters, but Dean insists on Sam staying with Kevin to research the Tablet while he investigates.
Songs: Joey Scarbury
-- Greatest American Hero Theme (Believe It or Not)
Sonny, a man who runs a boy's home, calls Dean in after a mysterious death occurs. When Sam wonders how his brother knows Sonny, Dean explains that he spent two months there when he was 16 after being arrested for theft.
When a mysterious abductor targets members of a virgin chastity group, Sam and Dean go undercover to track down the killer when Sheriff Jody Mills asks them for help. However, Dean disappears and Sam and Jody end up tracking him down.
The angels fight each other in bloody civil war, and Castiel is swept up in the conflict. Meanwhile, Dean realizes that Ezekiel is not who he claims to be and tries to warn Sam with dire results.
Dean and Castiel make a deal with Crowley to contact Sam's consciousness so he can expel the angel Gadreel from his body. However, Abaddon is hot on their trail and Crowley has plans of his own.
Crowley turns to Dean for help to locate the First Blade, the only weapon that can kill Abaddon. However, they soon discover that the trail leads to Cain... the Father of Murder and the most powerful demon of all time. Meanwhile, Sam asks Castiel for help when they need to extract the remaining grace from Sam's body to track Gadreel.
Six months after his disappearance, Garth turns up injured in a hospital. Sam and Dean arrive separately to investigate and soon discover that their friend has undergone a startling transformation... and found others who share his condition.
Two victims die and the fat is stolen from their bodies. Dean and Sam investigate a local spa and go undercover, and discover that a monster is preying on the overweight.
While Sam and Dean try to track down Kevin's mother, Castiel is captured by an old battle-comrade and learns more about the factions of angels.
The brothers investigate a mysterious murder that was apparently caused by a ghost, and discovers that the Ghostfacers, Ed and Harry, are already on the case. However, the facts don't add up and the Winchesters realize that something more is going on.
Songs: The Wind and The Wave -- This House is a Hotel
Dean is frustrated when he can't reach Crowley who has promised to find The First Blade. When Crowley finally calls Sam and Dean, he tells them he fell off the wagon and has been injecting human blood and needs their help. To make matters worse, he had a demon helping him find blood, but she sold him out and told Abaddon that he and the Winchesters were searching for The First Blade. The brothers need to find the blade before Abaddon does, so they enlist the help of a former member of the Men of Letters.
Source: The CW
Dean struggles with the after effects of the Mark of Cain. Meanwhile, Sam hears about a case where straight-laced people are turning into violent murderers. Sam suspects possession and suggests to Dean that they investigate, but Dean tells him to go without him. While interviewing the local townsfolk, Sam meets an elderly woman named Julia, who tells him the Men of Letters came to town in 1958. Josie tells Sam the story of a young man named Henry Winchester and his female companion, Josie Sands. While Sam is away, Crowley tests Dean.
Source: The CW