As the town preps for Halloween, a high-scoring rival shakes things up at the arcade, and a skeptical Hopper inspects a field of rotting pumpkins.

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.

Dustin adopts a strange new pet, and Eleven grows increasingly impatient. A well-meaning Bob urges Will to stand up to his fears.

An ailing Will opens up to Joyce -- with disturbing results. While Hopper digs for the truth, Eleven unearths a surprising discovery.

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.

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.

Psychic visions draw Eleven to a band of violent outcasts and an angry girl with a shadowy past.

Eleven makes plans to finish what she started while the survivors turn up the heat on the monstrous force that's holding Will hostage.