Sam and Castiel believe that they found a way to track Gadreel. Dean and Crowley team up to find the first blade, which is in the hands of the biblical Cain.
Abaddon makes a deal with Crowley to stop the Winchesters and recover the first blade. Castiel tries to bring Gadreel to his side in the war against Metatron.
Dean is a demon and running amok with Crowley while Sam tries to figure out what happened to his brother. Meanwhile, Castiel is dealing with his diminishing grace.
Crowley is worried about Dean getting out of control, giving him a target to feed the mark. Sam struggles to escape from Cole. Hannah tries to convince Metatron to give Castiel's grace back.
Sam continues to try to save Dean from the Mark of Cain. Realizing that Dean's antics are causing problems for him in hell, Crowley seeks help from a reluctant Castiel.
Jody Mills is matched with an overeager partner during a mandatory sheriff's retreat; when a gruesome corpse is discovered, Jody calls Sam and Dean to help investigate.