Immediately after the fall of the angels caused by the angel Metatron, the Scribe of God, Sam falls into a coma from the effects of the trials to close the gates of Hell and almost dies. With Castiel unable to help (having lost his grace), Dean seeks the aid of another angel named Ezekiel, whose only option to save Sam from his wounds is to possess him. Dean accepts, and helps Ezekiel trick Sam into giving his consent against his knowledge. The three of them, with Kevin (and Crowley as their prisoner), work to find a means to put the angels back in Heaven and are also forced to deal with Knight of Hell, Abaddon, who is attempting to seize control of Hell in Crowley's absence and enforce her reign of Hell on earth. Also a newly human Castiel must continue to run from the thousands of angels who blame him for their setbacks including many of whom are now lead by Bartholomew and Malachi seeking to restore themselves back to Heaven under their respective leadership's. Sam and Dean (with the help of Ezekiel) deal with regular hunting cases with help from old friends such as Charlie and Jody, but over time Sam begins to notice that something isn't right with him which Dean wants to tell Sam about but Ezekiel insists that his presence must remain secret. Eventually, Metatron returns to Earth and Ezekiel is revealed to actually be the angel Gadreel, the former protector of the Garden of Eden picked by God Himself to protect the Garden but failed by letting Lucifer into the Garden and was then punished by being locked away in Heaven's darkest dungeon. Metatron makes a deal with Gadreel to rebuild Heaven together by allowing certain angels to return which Gadreel, seeking to redeem himself accepts. Dean discovers Gadreel's deception and tries to warn Sam, but Gadreel takes full control and kills Kevin. Meanwhile, Castiel reclaims his powers by stealing the grace of another angel. Dean and Castiel team up with Crowley to expel Gadreel from Sam's body, but are forced to let the King of Hell go in exchange for his help.
