On the Head of a Pin (S04E16)

Someone has found Lucifer's sword and is using it to kill angels. Castiel (recurring guest star Misha Collins) and Uriel (recurring guest star Robert Wisdom) capture Alastair (recurring guest star Christopher Heyerdahl) and ask Dean to use the torturing skills he learned in Hell to extract information so they can stop the murders. Sam is concerned Dean can't handle the job but Dean agrees to do it. However, when Alastair reveals some shocking information, Dean's world is shattered. (Warner Bros. UK)