Castiel 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.

Abaddon finally gets something that she can use as leverage against Crowley to force him to lure the Winchesters into a trap. Meanwhile, Castiel rallies his forces and asks Sam and Dean to come in and help him interrogate a captive angel with ties to Metatron.

After an angel carries out a suicide attack on an ice cream shop to kill one angel from another faction. Sam and Dean investigate and discover that the target was one of Metatron's angels and that Castiel may be responsible.

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.