By “Chapter Six: E Pluribus Unum,” two out of three of the groups unraveling mysteries on Stranger Things know that the Russians are involved, but it’s the third group that might be in the most immediate danger.
In the Russian lair beneath Hawkins, Steve (Joe Keery), Dustin (Gaten Matarazzo), Erica (Priah Ferguson) and Robin (Maya Hawke) have finally been noticed. When the comms officer Steve knocked out comes to, he alerts the base to their presence and the kids try to make a run for it. Steve and Robin hold off advancing soldiers so Dustin and Erica can escape through a duct, hoping that the younger kids will be able to get to help.
Steve and Robin are separated and interrogated, with Steve’s questioning involving a great deal of him getting punched. The Russians are unwilling to accept that these infiltrators really are just teens who scoop ice cream and found them by accident.
Dustin and Erica make their way to a room full of acid storage tubes, a small vehicle and a curious looking cage with accompanying cattle prod. Erica commandeers the cattle prod and Dustin finds keys for the vehicle, but they don’t use their new assets to seek freedom and help.
Steve and Robin are reunited, bound together on stools and drugged with truth serum by a menacing “doctor.” Although Steve’s story doesn’t change when they’re questioned together afterwards, Robin adds that they picked up the Russians’ code and that two kids who scoop ice cream for a living cracked it in a day. They tell their captors that Dustin will have escaped by now and that the cavalry is coming.
Just then, alarms sound. Everyone but the doctor runs to see what’s happening, and the Russians find a giant hole eaten through the floor by acid. Dustin and Erica burst into the room where Steve and Robin are being held, and Dustin uses the cattle prod to subdue the doctor. They’re getting their friends out of there.
Bonus: bonding! Dustin tells Erica the whole background of the Upside Down while they’re on their solo adventure, and she believes everything except that her brother was there. Then, as she does equations quickly in her head, Dustin realizes that like him, she is a nerd, and seems to convince her of this. Meanwhile, Robin reveals that she had a huge crush on Steve when they had a class together sophomore year, and he responds that he wishes he’d noticed her then– maybe she would have helped him pass that class, and he’d be on his way to college now.
Also on the trail of the Russians are Joyce (Winona Ryder) and Hopper (David Harbour). Although their efforts to get answers from Alexei (Alec Utgoff) are initially unsuccessful, Hopper realizes that the Russian is more scared of his compatriots than his captors. He shoves him, unscathed, out of Murray’s (Brett Gelman) compound and throws the keys to his cuffs and the car after him. Joyce and Murray are sure the man will escape, but true to Hopper’s instincts, he is cowed by the threat of freedom and comes inside docilely to tell what he knows.
Alexei confirms that the Russians are opening the gate between realities, and he says that although there have been attempts to do it in Russia, Hawkins is a more viable place because the gate has been opened there before. Hopper jumps on the phone and sends a coded message to his friend in high places that the gate is being opened by the Russkies, and that he needs to come right away. Joyce, underwhelmed by Hopper’s sense of urgency, calls back and lays into the man on the other end of the line until she’s convinced that he’s taking them seriously.
Joyce, Hopper and Alexei head back to Hawkins, leaving Murray to deal with the fact that he’s been compromised by their calls and needs to relocate.
The rest of the gang is at Eleven’s (Millie Bobby Brown) house, bickering over how much they should trust her to know her own limits while she searches for Billy (Dacre Montgomery) in her psychic space. Mike (Finn Wolfhard) inadvertently declares his love for her (to everyone except her) while defending his degree of concern for her safety.
Elle does find Billy, and everyone agrees that if he’s sitting on his bed on the 4th of July, he wants to be found and it’s a trap. Nonetheless, Elle goes in deeper, still searching for the source.
She gets pulled into Billy’s formative childhood memories of an idyllic surf session on the beach under his mother’s watchful eye, through episodes of his father physically abusing her in front of him and berating him for being a “pussy,” through the aftermath of his mother leaving them and Max (Sadie Sink) being thrust on him as a new sister, and into the eye of his emotional storm, where the location of the Mind Flayer lives. Elle is able to relay the name of the steelworks to the group, and Nancy (Natalia Dyer) and Jonathan (Charlie Heaton) find the address in the Yellow Pages.
When Elle tries to return to her friends, she finds she’s stuck in a bizarro version of her living room. Billy, puppeted by the Mind Flayer, enters and tells her that now they can all see her and that they’ve been building something. First they’ll end her, then her friends and then everything else.
She manages to escape back to reality, shaken and screaming. As Mike embraces her, the flayed are activated all around Hawkins and begin marching hollowly to the steelworks. First Heather (Francesca Reale), then her mother, then Mrs, Driscoll (Peggy Miley), then others, shamble towards the Mind Flayer, collapse before it and explode into goo, oozing into it and joining the collective funk of its body.