In his attempt to break his deal with Crowley, hunter Bobby Singer manages to capture a Crossroad Demon to torture for information on Crowley's real name. After capturing the demon, Bobby manages to get his hands on her human bones to use as leverage.
After the demon refuses to cooperate, Bobby shows her the sack containing her human bones and prepares a flamethrower. Though the demon protests that burning a demon's human bones having any effect on them to be a myth, Bobby scorches the bones with his flamethrower. When the demon's human bones are scorched, burns appear on her vessel and the demon experiences intense pain, eventually telling Bobby that Crowley is now the King of Hell. After a brief interruption by Marcy Ward, Bobby demands Crowley's real name and scorches the bones with his flamethrower continuously, causing the demon to suffer burns until she relents and identifies Crowley as Fergus McLeod.
After getting the information from the demon, Bobby douses the bones in lighter fluid as the demon demands that Bobby exorcise her. Bobby burns the bones with his flamethrower, causing the demon and her vessel to burn to ash, killing the Crossroad Demon.
After learning Crowley's real name, Bobby sends the Winchesters to Scotland to threaten Crowley's bones in an effort to break his deal. Though Crowley claims that burning a demon's human bones to kill them being a myth, Bobby reveals that he burned the Crossroad Demon's bones to kill her, causing Crowley to finally relent.