Supernatural Season 6 Episode 13: Unforgiven

Sam starts to have flashbacks to a case he worked on with Samuel before he reconnected with Dean. Sam receives a mysterious text with coordinates to a small town, so the brothers decide to investigate. Dean is surprised when the townspeople start telling him some of the things Sam did while he lived there.

Supernatural Season 5 Episode 13: The Song Remains the Same

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.

Supernatural Season 4 Episode 13: After School Special

Sam and Dean investigate a haunting at one of their old high schools where we will see what school was like for the brothers.

Supernatural Season 3 Episode 13: Ghostfacers

Sam and Dean inexplicably encounter the Hell Hounds while investigating a case that John failed to crack years earlier and become fixtures in their pilot for a reality show called Ghostfacers.

Supernatural Season 2 Episode 13: Houses of the Holy

In Providence, Rhode Island, the local Gloria kills a man claiming that an angel in a beautiful white night had chosen her for redemption and asked her to stab the sinner to accomplish God's will. Dean and Sam investigate the case and they discover that other people had been visited by the angel and committed murders. Further, the angel has appeared after the death of Father Gregory, who was murdered on the steps of his church two months ago. When Sam is visited by the angel and asked to kill a man, the skeptical and atheist Dean confronts the faith of Sam telling that men cannot be angels and the light is an angry spirit indeed.

Supernatural Season 1 Episode 13: Route 666

Dean gets contacted by his first love, an African American woman, about racist murders that occur on a desert route, caused by a truck that seems driver-less.