The sixth episode of Stranger Things’ third season, Chapter Six: E Pluribus Unum, opens with the aftermath of the attack at the abandoned steelworks. The group realizes that they have no choice but to destroy the Mind Flayer’s source materials in the steelworks in order to halt the opening of the gate to the Upside Down.
Billy and the Mind Flayer’s army of infected citizens are still advancing towards the final battle. Meanwhile, Joyce and Hopper are working together to decode the map that they found at the Russian’s secret facility, discovering that it leads to the underground bunker under Starcourt Mall.
At the mall, Dustin, Steve, and Robin are still trapped by the Russians, trying to find a way to escape. They realize that they must reach the roof to send a distress signal using Erica’s walkie-talkie. However, their progress is impeded when they run into Grigori, the Russell Donovan-like assassin that the Russians have sent to silence them.
Elsewhere, Nancy and Jonathan continue their investigation in Mrs. Driscoll’s house and discover a site that was used to create the flayed army. They also suspect that the corrupted townspeople are in fact an alternative means of opening the gate and connecting the real world and the Upside Down.
The episode ends with the explosive final showdown against the Mind Flayer’s army at the steelworks. The protagonists have to fight against the Flayed and the Mind Flayer, armed with only the now-weakened Eleven’s telekinesis, in order to achieve their goal. Ultimately, the group succeeded and destroyed what was left of the Mind Flayer’s source material, but not before Eleven had to use all of her powers to fend off the horde.
As the episode comes to a close, everyone escapes and finds each other outside of the steelworks, bringing together all of the separated groups. But the Mind Flayer is still out there, and the group realizes that they’ll have to face the horror again if they are to stop it for good. The episode ends with viewers left breathless, wondering how they will make it out alive in the last two episodes of the season.