A few days before Halloween, Sam and Dean launch an investigation into two mysterious deaths in a small town. The brothers find hex bags and deduce that a witch is sacrificing people to summon a dangerous demon named Samhain. Castiel arrives in town and tells Sam and Dean that the freeing of Samhain is one of the seals that will lead to freeing Lucifer. To protect the seal by killing the witch, Castiel brings a specialist angel named Uriel (Robert Wisdom) to smite the entire town to be sure of killing the witch, but is convinced by Dean not to and to give the Winchesters a chance to stop the witch. Samhain is freed despite their best efforts and after Ruby's knife is knocked out of his hands, Sam is forced to use his powers to exorcise the demon, stopping the rise of the ghosts and demons he was causing; however, the seal is still broken. Uriel warns Sam against using his demonic powers and says that he will kill Sam as soon as Sam ceases to be useful to the angels. Still annoyed by Dean stopping him from smiting the town, Uriel tells Sam to ask Dean what he remembers from Hell, implying that Dean does, in fact, remember what happened to him there. Meanwhile, Castiel reveals to Dean that his true orders were always to follow Dean's orders to test his leadership under battlefield conditions, though even he does not know if Dean passed the test. He confesses that he does not know what the "right" choice would be and that he has his own doubts, though he does not show them. Lastly, Castiel warns that hard times are ahead and says that he doesn't envy Dean for what is to come.
Source: Wikipedia
Source: Wikipedia