Chapter 1: Susie Do You Copy
On June 28, 1984, Soviet generals give a group of scientists a year to develop technology to force open a portal to the Upside Down. A year later, in the middle of the summer of 1985 in Hawkins, the new Starcourt Mall has caused other town shops to close down, angering townspeople. Mike and Eleven have developed a romantic relationship and Hopper talks to Joyce seeking advice on how to split the two apart. She suggests he write a "heart to heart" speech for Eleven. Dustin comes back from summer science camp, and encourages Mike, Will, Lucas, Eleven, and Max to help set up a makeshift radio so he can contact Suzie, a girl he met at camp. One night, the power goes out across Hawkins, which shakes Will, and at a nearby abandoned steel mill, a strange entity appears. Nancy has started a job at the local paper, under editor Tom Holloway and co-worker Bruce. She secures a tip about a strange event. Dustin records a strange transmission coming through his transmitter of a man speaking Russian. Billy later drives by the mill, hits something and is dragged inside.
Chapter 2: The Mall Rats
Billy is dragged into the Upside Down, where he encounters his doppelganger. Instead of having a heart to heart, Hopper tries to distance Mike from Eleven. Later, Eleven and Max run into Mike, Will and Lucas at the mall, where Eleven breaks up with Mike. Nancy and Jonathan follow up on her lead and find Mrs. Driscoll had caught a rat that was eating her new fertilizer. When they're not looking, the rat implodes into an amorphous organic mass and escapes. Hopper asks Joyce on a date, but she gets caught up in discovering why all the magnets lost their magnetism, and misses the dinner. Dustin, with the help of Steve and his co-worker Robin, translate the Russian sentence. Steve discovers that the song Daisy Bell, heard in the background of the Russian message, is identical to the music played from a toy horse in the mall, suggesting the message originated locally rather than from Russia. Meanwhile, Billy struggles with nightmares during lifeguard duty and guided by a strange voice connected to his doppelganger he saw in the Upside Down, he abducts fellow lifeguard Heather Holloway and takes her to the mill to be possessed by the entity there.
Chapter 3: The Case Of The Missing Lifeguard
Max encourages Eleven to use her powers to "spy" on Mike. Later, when spying on Billy, he senses her presence and Eleven sees Billy subduing Heather. Max and Eleven try to track down Billy, but fail to find him and Heather at work. Nancy finds out more about the strange rat behavior, but she is made fun of by the men at the paper. Attempting to find the rat from Mrs. Driscoll, Nancy and Jonathan find that Mrs. Driscoll is feral herself. Will has a falling out with Lucas and Mike following a D&D game. Robin happens across the clues to decode the message, indicating something will happen at the mall that night. That night, Dustin, Steve, and Robin spy on armed Russian men covering a shipment to the mall. While Hopper is angry at Joyce for missing their date, aware she is considering moving out of Hawkins, Joyce reiterates what Clarke told her, and look for signs of such a device at the abandoned Hawkins Lab where Hopper is attacked. Eleven and Max find Billy and Heather apparently okay with Tom and his wife. Billy sneers as they leave, which Will senses. Billy and Heather then knock out her parents.
Chapter 4: The Sauna Test
Heather take her parents to the mill, where they are also possessed. Later, Nancy and Jonathan are fired by Tom. Still curious, Nancy goes to visit Mrs. Driscoll at the hospital. Eleven and Max reunite with Mike, Will, and Lucas after hearing about Will's latest sensing. The group determine that the Mind Flayer still resides in the real world, having possessed Billy. That night, the five trap Billy in the pool's sauna, confirming he is possessed. Billy gains superhuman strength and breaks free, at the same time that Nancy witnesses Mrs. Driscoll similarly transform. Hopper recalls seeing the Russian man that attacked him, Grigori, previously meeting with Mayor Kline. Hopper and Joyce force Kline to reveal that Grigori works for the owners of Starcourt, who have bought up additional abandoned properties around Hawkins. Kline alerts Grigori as Hopper and Joyce search those locations. At Starcourt, Dustin, Steve, and Robin enlist Erica to break into the storeroom, finding too late that it is an elevator as it takes them deep below the mall. Billy regroups with Heather at the mill, where dozens of other Hawkins citizens have been possessed.
Chapter 5: The Flayed
Hopper and Joyce discover one of the abandoned properties has a hidden laboratory. They get into a fight with Grigori and escape with Dr. Alexei, a Russian man who helped build the gate to Upside Down. Alexei only speaks Russian, so Hopper decides to go to Murray who can help translate. Grigori tries to follow and loses the trail. Dustin, Steve, Robin, and Erica hide from Russian men unloading the boxes from the elevator, and follow them out after they leave, discovering a massive Russian base under Starcourt. Attempting to find a communications room, the four discover a large testing area where scientists are trying to open the portal to the Upside Down. Nancy and Jonathan meet with Will and the others, and confirm their experiences from the previous night. They decide to let Mrs. Driscoll lead them to where Billy is. While the other children wait downstairs, Nancy and Jonathan find Mrs. Driscoll gone and an enraged Tom and Bruce waiting for them. Nancy and Jonathan fight the two and upon killing them, their bodies dissolve into organic masses which join together, forming a beast.
Chapter 6: E Pluribus Unim
As the Mind Flayer attacks Nancy and Jonathan in the hospital, Will senses its presence, and Eleven arrives in time to overpower it; it slinks off into the sewers. In the Russian base under Starcourt, Steve and Robin are captured, drugged, and interrogated, but Dustin and Erica arrive to rescue them. With Murray's translation, Hopper and Joyce learn from Alexei of the Russian efforts to build gate machines to access the Upside Down, including one under Starcourt; Hopper calls Dr. Owens to warn the government. Grigori corners Klein at the Independence Day fair, demanding he step up efforts to find Hopper's group. To find the Mind Flayer, Eleven uses the same method of accessing Billy's memories as she had used with her mother. After seeing his troubled childhood, she finds the eye of the stormat the steel mill. As she pulls out of his mind, Billy grabs her, and the Mind Flayer senses her location, in Hopper's cabin. Across town, those possessed by the Mind Flayer converge on the mill, and congeal into a larger beast.
Chapter 7: The Bite
Eleven and the others determine the Mind Flayer is coming for her since she was the one who previously closed the gate. Will senses the Mind Flayer approaching and it attacks them before they flee. Dustin and Erica drag a drugged Steve and Robin to the movie theater in Starcourt. Eleven's group break into a hardware store to help treat her wounds and gather more supplies. Suddenly, Dustin contacts them over walkie-talkie to explain their situation before he loses battery power. Eleven uses her powers to check on Dustin, so the group takes off for the mall. Steve admits that he has feelings for Robin, but she comes out to him as a lesbian. Hopper's group make their way to the fairgrounds in Hawkins to find the children where they are spotted by Klein, who alerts the Russians. Alexei is fatally shot by Grigori in front of Murray. Murray, Hopper, and Joyce evade several Soviet agents and learn the agents are looking for the children at the mall. At the mall, Eleven's group arrives in time to stop the Russians from shooting Dustin's group. Eleven collapses in front of the children, her wound pulsing with a strange growth.
Chapter 8: The Battle of Starcourt
Eleven rids herself of the growth as Hopper's group arrives. Plans are made to take Eleven to safety, while Hopper, Joyce and Murray will shut off the machine, with Dustin and Erica navigating for them from his radio tower. Dustin enlists Suzie's help for a necessary code, Planck's constant. Billy and the Mind Flayer trap Eleven at the mall. Billy seizes Eleven for the Mind Flayer while the others distract it with fireworks. Eleven is able to awaken Billy's mind from his memories, and Billy sacrifices himself to protect Eleven. Hopper fights with Grigori in the gate room as Joyce prepares to trigger the shutdown. Hopper throws Grigori into the machine, causing it to go haywire and block his exit. Hopper nods at Joyce to trigger the shutdown, seemingly disintegrating everyone in the gate room, and stopping the Mind Flayer. As Dr. Owens arrives with military forces, Eleven sees from Joyce's expression that Hopper is gone. Three months later, Joyce's family and a powerless Eleven prepare to move out of Hawkins. Joyce gives Hopper's written speech to Eleven. In Kamchatka, Russian guards are instructed to feed a prisoner, but "not the American", to a captive Demogorgon.
Final Thoughts:
Great Season
Great cliffhanger
Performances were great
New character additions are good