Sam and Dean are stumped. Somehow, a group of children's personal fears are becoming a reality and killing off a parent that each child has a certain hatred for.
Sam and Dean discover that Frank's hard drive, containing everything on the leviathans, is now in Dick's company building. To retrieve it, they ask for help from one of the employees, a young computer hacker.
Sam and Dean have possession of a Word of God, but are unable to read it. They find a young prophet that can help, but unfortunately, the angels and leviathans are after him, too.
To officially kill the leviathans, Sam and Dean need the blood of an Alpha. But Dick knows what the Winchesters are up to and sends his men after them.
Sam and Dean make a plan to storm Dick's company building and kill him once and for all, with help from Castiel and Meg. Providing Bobby doesn't get to Dick first.
Dean returns from Purgatory, one year after the fight with the Leviathans. After reuniting with Sam, they find out that Kevin escaped Crowley with another Word of God that may hold the key to closing the gates of Hell forever.
Dean assists the vampire, Benny, who helped him escape from Purgatory. Together they go after the nest led by the vampire that bit Benny. Sam thinks back to his life before Dean returned.
Sam and Dean team up with Garth, who has taken over Bobby's job, as they hunt down a Specter that's possessing innocent people who have a grudge against someone.
Crowley has kidnapped Kevin and the rest of the prophets that are able to read the Word of God. Castiel mysteriously returns from Purgatory and helps Sam and Dean rescue Kevin.
Castiel decides to become a hunter, like Sam and Dean. But his first day on the job is a doozy when they investigate a series of murders caused by old cartoon gags. Meanwhile, Sam thinks back to his first time meeting Amelia's father.