Season synopsis
Contains spoilers for this season and earlier seasons.
Sam and Dean search for Jack after Kelly and Castiel die, while they disagree over whether Lucifer’s son can be trusted. Jack is powerful but inexperienced, and Sam tries to teach him restraint as Castiel returns. Dreamwalker Kaia helps Jack open a rift to find Mary; Sam and Dean land in the dangerous Bad Place while Jack reaches the war-torn alternate Earth. The separate journeys leave the brothers searching for a way home and for their mother.
In Apocalypse World, Mary has joined the human resistance against its Michael, who rules through a campaign against humanity. The Winchesters and their allies work to open a route between the worlds, bringing back Mary and rescuing people who can escape. Jack’s growing attachment to Sam, Dean and Castiel makes Lucifer’s claim on him harder to accept. Lucifer tries to draw Jack away with promises of a shared life, while the Winchesters’ efforts to protect him repeatedly collide with the archangel Michael’s plan to invade their Earth.
The conflict reaches the bunker when Michael attacks and Jack drives him back. Lucifer then exploits Jack’s doubts, but Jack rejects him after learning that he killed Maggie. When Lucifer steals Jack’s grace and gains the upper hand, Dean agrees to become Michael’s vessel on the condition that he remains in control. Dean kills Lucifer using Michael’s power, but Michael breaks their agreement and takes control of Dean’s body. The season closes with the Winchesters having saved Mary and returned from Apocalypse World, but Dean now trapped behind the archangel’s eyes.