After Will sees something terrible on trick-or-treat night, Mike wonders whether Eleven’s still out there. Nancy wrestles with the truth about Barb.
Eleven makes plans to finish what she started while the survivors turn up the heat on the monstrous force that’s holding Will hostage.
Will’s connection to a shadowy evil grows stronger, but no one’s quite sure how to stop it. Elsewhere, Dustin and Steve forge an unlikely bond.
Nancy and Jonathan swap conspiracy theories with a new ally as Eleven searches for someone from her past. “Bob the Brain” tackles a difficult problem.