Supernatural - Season 9 Episode 11 First Born Between darkness and deliverance
Overview: Crowley turns to Dean for help to locate the First Blade, the only weapon that can kill Abaddon. However, they soon discover that the trail leads to Cain... the Father of Murder and the most powerful demon of all time. Meanwhile, Sam asks Castiel for help when they need to extract the remaining grace from Sam's body to track Gadreel.