After meeting Benny – the vampire who helped Dean escape from Purgatory in exchange for Dean resurrecting him – at the end of "Blood Brother", Sam immediately distrusts him, and asks Martin (a friend of their father's who had previously appeared in Season 5's "Sam, Interrupted") to monitor Benny. Martin contacts Sam in "Citizen Fang" to tell him that he believes Benny killed somebody, bringing the Winchesters to Carencro, Louisiana to help investigate. However, upon receiving an emergency text from Amelia and being unable to get a hold of her, Sam tears back to Kermit. He finds Amelia happily reunited with Don, and realizes that the text had been a trick by Dean to divert him from Benny. Enraged, Sam initially refuses to continue hunting with Dean in the following episode. Castiel – who has been mysteriously rescued from Purgatory – enlists his help in saving the angel Samandriel from being tortured by Crowley, forcing the brothers to reluctantly work together again. When forced by both Dean and Amelia to choose, Sam decides to rejoin his brother and fully commit himself to sealing Hell over returning to his normal life with Amelia. Around this time, Sam and Dean encounter their time-traveling paternal grandfather Henry Winchester and discover that through him, they are the legacies to an extinct secret society of compilers of supernatural information and artifacts known as the Men of Letters. Although they manage to subdue the demonic Abaddon, who has pursued Henry into the present, their grandfather is killed, leaving Sam and Dean the last link to the Men of Letters. They then inherit the bunker of the Men of Letters as their first real home.