Castriel investigates the mass slaughter of angels and finds a lone survivor... and an old friend. Meanwhile, Sam and Dean capture Gadreel, and Metatron begins the ending of his story.

After a suicide angel takes out an ice cream shop to kill one enemy angel, Sam and Dean investigate and discover that the target was one of Metatron's angels... and that Castiel may be responsible. Meanwhile, Metatron tries to consolidate his hold over the angel factions with promises that he will restore them to Heaven.

After attacking Gadreel, Dean leaves with Crowley to track down Metatron and kill him. Meanwhile, Gadreel takes Castiel into Heaven to try and break Metatron's connection to the angel tablet, stripping him of his powers.

Dean is a demon and running amuck 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.

Sam and Dean discover a group of witches "gone wild" and they attempt to stop them.