Angels get slaughtered by Lucifer's sword. Castiel and Uriel hold Alastair captive and ask Dean to use his newfound techniques in torture to take valuable information that can put an end to the murders. Dean learns some shocking facts from Alastair.
Sam and Dean seek help from Pamela, who sends the brothers to the spiritual realm. They discover Alastair attempting to break the seal causing mayhem in the mortal world by stopping death from occurring in a small town.
A siren casts a spell on Sam and Dean while they are on a mission in Iowa, leading to their violent behavior.
Sam and Dean investigate a haunting at one of the high schools they attended as teenagers.
Sam and Dean are faced with magicians delving in black magic. They investigate after several people wind up dead in ways similar to the illusions the magicians perform on stage.
Sam and Dean investigate a house occupied by a female ghost, but when a new family moves in things take a turn for the worse.
Dean and Sam figure out why Castiel and Uriel want Anna dead. Alastair and his minions try to track down Sam, Dean and Anna.
Sam, Dean, and Ruby look for Anna who hears the voices of angels. When Ruby seemingly betrays the brothers and leaves with Anna, Sam enlightens Dean on how Ruby saved Sam's life while Dean was in Hell.
The Winchesters investigate a town wishing well that really grants wishes... at a terrible cost.
Sam and Dean meet Castiel and his fellow angel Uriel, who warn the brothers to avoid intervening in a town where a witch is attempting to summon the demon Samhain, opening one of the Seals.