After Mick Davies is killed the brothers acknowledge that the Men of Letters have gone rogue. Meanwhile, the president has made his assistant Kelly Kline pregnant and Castiel realizes that a Nephilim is to be born. Sam, Dean and Castiel try convince Kelly about the impending danger. While Lucifer has been captured and being tortured by Crowley. Sam and a few hunters gather to defeat the Men of Letters while Castiel retrieves Kelly after killing Dagon. Lucifer is released by Crowley's minion demon and heads on to find his son. In the finale Kelly gives birth to the Nephilim, while Crowley sacrifices himself to kill Lucifer. Crowley and Castiel die trying to kill Lucifer while Mary and Lucifer are pulled into the rift created by the Nephilim's birth. Dean kneels down in despair after witnessing Castiel being killed while Sam is shocked when he arrives to see Jack the Nephilim grown into a teenager.