An increasingly concerned Nancy looks for Barb and finds out what Jonathan's been up to. Joyce is convinced Will is trying to talk to her.

A frantic Jonathan looks for Nancy in the darkness, but Steve's looking for her, too. Hopper and Joyce uncover the truth about the lab's experiments.

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.

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.

Dr. Alexei reveals what the Russians have been building, and Eleven sees where Billy has been. Dustin and Erica stage a daring rescue.

As Hopper braces to battle a monster, Dustin dissects Vecna's motives — and decodes a message from beyond. El finds strength in a distant memory.