Shiz is getting REAL in “Chapter Four: The Sauna Test,” the scariest episode of Stranger Things Season 3 so far!
The pettiness of boy/girl relations is quickly overshadowed by the return of the Mind Flayer. Will (Noah Schnapp) has a theory: he believes that when his mother got the Mind Flayer out of him, Eleven (Millie Bobby Brown) inadvertently locked it out of the Upside Down when she closed the gate– and it needed a new host.
The boys convince the girls to meet up for a Code Red, and as Will walks them through the indicators of a host, a clear suspect arises: Billy (Dacre Montgomery). Max (Sadie Sink) really doesn’t want to believe her brother could be hosting the Mind Flayer, but she goes along with her friends as they watch him lifeguarding while wearing a long-sleeved shirt and covering his legs with a towel.
With Will’s guidance, the kids develop a plan. Because the Mind Flayer likes it cold, they’ll trick Billy into the sauna at the YMCA after the pool closes and crank up the heat. They assemble a variety of restraints and other tools, and when Billy retreats into a cold shower at the end of his shift, they set their plan in action.
They succeed in luring a furious Billy into the sauna and locking him in, watching him sweat through the sauna window. He rails at them, shouting threats. Then he collapses into a ball on the floor, begging Max to help him and claiming that “he” made him do the bad things.
Max, sucked in by her sympathy for her brother, approaches the sauna window. Fortunately, Will’s goosebumps alert him to when the Mind Flayer has been activated in Billy, and they convince Max to move away just before Billy punches through the window with a shiv in his hand, intending to slash his little sis.
He escapes the sauna, black veins popping all over his sweat-drenched body, and enters a battle royale with Elle. When it seems like he might have the upper hand, Mike (Finn Wolfhard) strikes him from behind and draws his attention. As Billy moves in on Mike, Elle recovers enough to throw the human hair mop through a wall with her powers.
Billy runs off into the night, back to Heather (Francesca Reale) and the steel works, where the Mind Flayer is quietly assembling an army of possessed townspeople.
Meanwhile, at Starcourt, Robin (Maya Hawke, Ethan and Uma’s daughter, and thereby another callback to Reality Bites) has a plan– and it involves plans. Because they can’t likely get past the armed guards outside the box room off the loading dock, she goes downtown to buy copies of the blueprints for the mall. On them, she sees a clear path from Scoops Ahoy to the box room via air ducts.
Erica is a mall rat who spends her summer days demanding free samples at Scoops Ahoy, and she negotiates free ice cream for life in exchange for her role in what she calls “operation child endangerment.” After the mall closes, she enters the duct wearing two flashlights taped to a helmet and crawls through to the box room. Once inside, she opens the exterior door for Steve (Joe Keery), Dustin and Robin.
They open one of the boxes to see what’s inside and discover the kind of secure case you’d expect to find plutonium in. Instead, there is a sparkling green substance held in the same kind of tube. They steal one, but they can’t get the door to open again. Erica takes charge and pounds one of the other buttons on the control panel, and the room drops. It’s an elevator! And they’re on their way DOWN.
Back at The Hawkins Post, Nancy (Natalia Dyer) and Jonathan (Charlie Heaton) get fired by their abnormally sweaty boss for pursuing the story they’d been told to drop. As they drive home, Jonathan attacks Nancy for her insensitivity to the importance of an income for him and she feels frustrated that he doesn’t care about pursuing the truth. They agree that maybe they don’t understand each other anymore, and she goes home in tears over the loss of her job and her boyfriend.
Karen (Cara Buono) gives her the ideal shoulder to cry on. After hearing her daughter out, she responds that the world is a tough place that tries to push you down, but that Nancy is strong and smart enough to keep fighting. She tells her to keep following her story and to sell it to a bigger paper and teach the jerks at the little local paper a lesson when they see what they’ve missed.
Nancy takes her mom’s advice immediately and goes to the hospital to visit the old woman she found eating fertilizer. Mrs. Driscoll (Peggy Miley) is resting peacefully when Nancy arrives, but at the same time the Mind Flayer is activated in Billy, her heart monitor goes crazy and she lurches forward in her bed with the same black veins popping out all over her face and body that Billy’s got. Nancy, horrified, looks on with her reporter’s notebook in hand.
While the kids are all entering mortal danger, Hopper (David Harbour) seems safe. He wakes up in his own home with Joyce (Winona Ryder) caring for him. She tells him that the thug who attacked him at the lab rode off on a motorcycle, and he knows exactly who it was– the same guy he saw leaving Mayor Kline’s (Cary Elwes) office a couple of days earlier.
They speed to the Mayor’s office, where Joyce watches the secretary as Hopper beats the truth out of the Mayor: the thug brings him gifts and incentives to help someone buy up big properties on the edge of town. Properties near the power plant.
Hopper forces the Mayor to give him all of the paperwork he has on the land deals, and he and Joyce set out to investigate all of them, looking for the machine that is generating magnetic fields in Hawkins.