The sixth season begins about a year after the end happenings of the fifth with Dean living a normal life with Lisa Braeden and her son Ben. Sam mysteriously and miraculously returns to Earth and reunites with Dean, who leaves his new life behind. Sam has been working with their grandfather, Samuel Campbell (their mother's father), in order to capture the Alpha monsters (first of the gene pool). Bobby eventually gets his soul back from the crossroads demon Crowley, who has apparently become the King of Hell. It is eventually discovered that Samuel is following Crowley's orders in exchange for the resurrection of his daughter, Sam and Dean's mother. Castiel is barely helpful anymore because a civil war in Heaven against the archangel Raphael (who wants to take over Heaven, free both Michael and Lucifer from the Cage, and start the Apocalypse again) has taken its toll. Crowley wants to use the Alpha Monsters to locate Purgatory, a supernatural realm that is filled with the souls of every monster that has ever been killed (vampires, werewolves, wendigos, skinwalkers, even shapeshifters etc.) and in which there are a vast collection of souls that could be used for power. Castiel brought back Sam without his soul, and Dean implores the help of the Horseman Death in order to retrieve it. Death puts a wall up in Sam's mind so that he will not remember Hell. Sam's original personality is restored with no memory of the past year and a half. It turns out Castiel made a deal with Crowley for both of them to receive half of the souls in Purgatory. Dean doesn't like the idea and tries to stop the duo. To stop the Winchesters and Bobby Singer, Castiel knocks down the mental barrier in Sam. Castiel betrays Crowley, who then allies himself with Raphael and performs the ritual to open the doors of Purgatory. It fails because they had fake dog's blood and Castiel appears full of power from having done the ritual himself. He obliterates Raphael and Crowley escapes. When the Winchesters try to reason with Castiel, he reveals that he is not an angel anymore, he has become the new God.
