The Byers Girl (On Pause until season 5)

Chapter Four: The Sauna Test

As Eleven brushes her teeth at Max's house, she mulls over her ominous visions of and encounters with Billy and Heather. Max assures her that everything is alright, despite Eleven's confusion over their behavior. As Max shows her a Wonder Woman comic, a hysterical Doris Driscoll is restrained by paramedics while Nancy and Jonathan watch.

Doris Driscoll continues to insist that she "has to go back" and desperately reaches for the Brimborn Steel Works as the ambulance drives by it. Tom and Janet Holloway awaken tied up in the basement of the mill. Heather and Billy ungag them. Heather tells her father that "there's no stopping it," and Billy tells them not to move. They leave as the Mind Flayer, now in physical form, attaches tendrils to the Holloways' faces.

Hopper awakens in his cabin being tended to by Joyce, recuperating from the injuries inflicted upon him by the Russian. The two theorize about his origins and motive, and Joyce reveals she wrote down the man's license plate, but only half of it is accurate.

Joyce mentions he was driving a motorcycle, and Hopper remembers a man in motorcycle gear emerging from Larry Kline's office. Max ignores Lucas's frantic radio calls until Mike calls her house phone and tells her to meet them at his place. Lucas tries to contact Dustin, who is busy staking out Lynx Transportation's covert operations. He formulates a plan with Steve and Robin to get inside their shipping room. Steve offers to fight the armed guard, but Dustin reminds him of his poor track record of losing fights. Robin gets an idea and grabs cash from the tip jar, running off.

At the Hawkins Post, an exceptionally angry and sweaty Tom berates Nancy and Jonathan for disobeying his orders and encouraging Driscoll, who turns out to be a paranoid schizophrenic. Under threat of a lawsuit from her family, he fires them both. The kids converge and Will explains his recent premonitions of the Mind Flayer's return.

Eleven insists she closed the gate, but Will remembers the piece of the creature that exited him and theorizes that Eleven locked it in their world with them. Y/n hugs Will worried for her brother. He realizes it would want a new host, and the group agrees to find out who.

Hopper tries to get answers out of Kline about the man who attacked him and threatens to expose his corruptions, but Kline reminds him that he knows of Hopper's previous illegal pill usage. Hopper beats Kline and threatens to cut off his finger until he explains he is working with the man, who works for the owners of Starcourt Mall. Kline raised property taxes to allow Starcourt to outcompete local businesses. Kline tells him the records of these dealings are at his mansion, but warns him the Starcourt people are extremely dangerous. Hopper drags Kline out with Joyce in tow.

Driving home, Nancy rants about the strange nature of their firing, but Jonathan insists she is convincing herself she is in the right. He argues with her for devaluing the importance of his job, as she leaves in a wealthy family while he does not. She fires back that he does not understand how humiliating her job was, and they both conclude that they do not understand each other anymore.

Nancy returns home in tears. Robin returns with Starcourt blueprints, which shows air ducts that lead from the ice cream parlor to the shipping room.
The three are initially excited, but realize none of them can fit in the vents. Erica arrives demanding more free samples, and Robin looks at her and gets an idea.

The kids observe Billy at the pool, who has covered the unshaded parts of his body. Mike remembers the Mind Flayer's avoidance of heat, and Will explains that the Mind Flayer is keeping Billy dormant until it needs him. Deciding they cannot risk him activating and attacking more people, the boys head into the locker room and formulate a plan to trap Billy in the pool's sauna after hours with Y/n being nervous she stops the boys.
"Be careful please, I love you all and I can't lose any of you, Billy can get aggressive and now that this thing might be using him he'll be even more aggressive" Y/n says worried.
The boys nod leaving.
"Will, I love you be careful and if anything happens all of you need to leave" she says hugging him tightly.
He nods his head hugging Y/n back with tears in his eyes.
He lets go and leaves with the other boys.
Y/n watches them walk away with a nervous look on her face.
Max walks over smiling.
"They'll be okay" she assures Y/n.
"Yeah, you're right" Y/n says with tears in her eyes.
Eleven walks over hugging Y/n tightly and Max joins the hug.

Back at the Mall, Erica checks the vents, confirming she is able to fit but demanding compensation. The group bribes her with "free ice cream for life" at her request, and she agrees to cooperate.

Kline shows Joyce and Hopper the financial records and again warns them that the Starcourt men are dangerous. Joyce notices a correlation with the bought properties: they are all close to the power plant. Hopper finds Kline trying to escape through his window and handcuffs him to his bed. When his wife later comes home, he shouts at her to bring him a phone.

Karen Wheeler listens to Nancy explain what happened, and tells Nancy she understands why she did not want to be wrong: because then she will be perceived as what most people already see her as. Nancy insists she gets her determination from her mother, and Karen tells her she is proud of her and that she should finish the story.

The kids prepare to trap Billy. Lucas tries to talk to Will about the previous day, but Will brushes him off, while Mike explains Hopper's interference in their relationship to Eleven in hopes of making up with her. Eleven muses that Hopper may be right that they are spending too much time together and quotes something Mike said while she spied on him in the void, shocking him.

Max and Y/n keeps watch over Billy, hoping he is not the host.
Back at the Mall, Erica crawls through the vents of Starcourt and opens the Lynx Transportation door, and her group comes down from the roof to join her.

Mike lures Billy to the sauna using his voice and a CPR dummy and Eleven stuns him by throwing him against the wall. The kids lock the door with a pipe and chain. Billy and Max lock eyes for a moment and he silently pleads with her, and Max orders the group to turn the sauna on, which they do.

At the hospital, Nancy sneaks into Driscoll's hospital room and looks at her medical chart, finding something that catches her attention. Driscoll's heart rate suddenly spikes and she begins breathing heavily, implied to be a result of Billy's predicament.

The Starcourt group extracts a green liquid in a canister from the marked boxes. Before they can examine it, the room shudders and when they attempt to operate the control panel to open the door, it plunges downwards, revealing it to be an elevator.

Billy aggressively demands to be let out as the sauna reaches maximum temperature. He begins to weep, apologizing to Max and Y/n for the things he has done and insisting that the "giant shadow" made him do them. As Max and Y/n try to comfort Billy through the door, he subtly grabs a piece of broken tile and the skin on the back of Will's neck flares up. Mike screams for them to get away from the door just as Billy shatters the glass on it, trying to stab Max. Y/n grabs Max protectively pushing her behind herself shielding her from him.

He removes the pipe blocking the door and Lucas shoots him in the head with his Wrist Rocket.
The lights start to flicker and Billy's veins blacken, and the lights in the hospital and Driscoll do the same. Billy breaks open the door and Eleven pins him to the wall with a barbell. He overpowers her and begins to strangle her, Y/n yells at him begging him to let her go, he looks at her with a look of sadness before his face turns back to an emotionless expression. Mike attacks him with the pipe, breaking his concentration long enough for Eleven to throw him through the wall. Mike briefly holds her, the kids and Y/n watch in astonishment as Billy runs away. Y/n runs over to Eleven making sure she's okay and hugging her tightly, she motions for Max to come over and the three of them sit on the floor together crying.

In the basement of the mill, Billy confirms to Heather that "the girl" was the one who attacked and nearly killed him, and his identity as the Mind Flayer's host is now compromised. Heather calmly tells him that Eleven cannot kill all of them, revealing a dozen people standing before the Mind Flayer.

To be continued...