Sam attempts so get on with his life without Dean, and he becomes rougher and more reckless. Bobby and Pamela try to connect with the other side to discover what happened to Dean.
Sam, Dean, and Bobby face off the angry souls of all the people they failed to save.
Castiel transports Dean back in time to 1973 where he meets the younger version of his parents and his grandfather and learns of his family's connection to the community of hunters.
Sam and Dean go on a hunt of a cannibalistic monster with the help of a skilled hunter.
Halloween is approaching and the brothers encounter a shapeshifter who changes into famous movie monsters like Dracula and the Wolfman.
Dean is stricken with a peculiar illness that literally frightens the people who get it to death. The brothers seek Bobby's help and race against time to rescue Dean.
Sam and Dean discover a witch that sacrifices people to conjure a powerful and dangerous demon while investigating two deaths in a small town.
Sam and Dean are called to look into a wishing well that begins to actually grant people's wishes.
Sam and Dean discover a new prophet called Anna Milton who can hear angels' voices and can figure out the plans of a demon against the angels.
Sam and Dean try to figure out why Castiel and Uriel want to get rid of Anna Milton, and they find themselves surrounded by angels and demons.
Sam and Dean are trying to stop a family from moving into a house, as there are urban legends saying it is haunted by demons.
Sam and Dean look into three magicians who use a magic textbook to perform actual magical spells.
Sam and Dean investigate a haunting at an old high school of theirs which takes us to how school was like for the duo in 1997.
Dean and Sam investigate a series of mysterious deaths when they are faced by a siren attempting to tear them apart.
Sam and Dean go to the spirit world to try to reveal the reason why the people of a small town keep having near-death experiences.
Dean is told to torture Alastair for information by Castiel and Uriel, but Castiel suspects there's a traitor among the angels when Alastair escapes.
In a parallel world, Dean and Sam are unrelated but working at a marketing agency together, and circumstance drives them to join forces to solve a mysterious series of suicides.
Sam and Dean discover an author has been writing about them since 2005, and wonder how he knows a lot about their lives.
Sam and Dean receive a call from a young man called Adam who claims to be their half-brother from their father's side. They have doubts at first but they later discover he's telling the truth.
Castiel is sent back to heaven. Meanwhile, Sam and Dean find themselves facing huge challenges helping his host body, Jimmy, fight off demons.
Sam is infected by human blood and gradually turns into something inhuman, so Bobby locks him in his panic room.
Sam joins Ruby in hunting down Lilith before Lucifer rises. Meanwhile, Castiel and Zachariah tell Dean his role in stopping Lucifer will be great.