In line with the nearing finale of "Supernatural" season 11, it is revealed that war is set to continue in Sam and Dean's world in episode 21 and they are set to save Castiel.

"Supernatural" season 11 episode 21 is entitled "All in the Family." According to Spoilers Guide, Dean is set to witness how Amara is torturing Lucifer. Also, the episode will see Dean and Sam plot a plan to end their worry and save Castiel from Amara's forces.

According to We Got This Covered, episode 21 is also set to see Chuck have a long discussion with Sam and Dean. As per the publication, the meeting of the three men is linked to how they are going to face and fight Amara, and stop her evil plans for good. The publication added that Sam and Dean plan to pursue saving Castiel, who has Lucifer in his body.

As per rumors, Samulet is also going to return in the episode; however, details on whether this come back impacts the current storyline are yet to be revealed.

Previously, Amara did another mischied in "Supernatural" season 11 episode 20, which is entitled "Don't Call Me Shurley." According to Spoilers Guide, Amara released an ominous fog on a small town and this made the residents angry. In line with the incident, Sam and Dean believed that the fog was a more potent iteration of the initial black vein virus Amara unleashed before.

While the duo worked alongside the sheriff to protect the town from Amara's deeds, it was revealed that their intervention was not effective.

"Supernatural" season 11 episode 20, "Don't Call Me Shurley," aired on May 4 while episode 21, "All in the Family," is set to air on May 11.