It's the summer of 1985 and Hawkins has a brand-new mall: the Starcourt. This palace of commerce has become a magnet for the town's teenagers, including Mike, Will, Dustin and Lucas. But while they are still close friends, all four have concerns of their own: Mike's burgeoning relationship with Eleven is threatened by her surrogate father, Jim Hopper; Will is still traumatized following his encounter with the Mind Flayer; Lucas is trying to figure out how to be a good boyfriend to Max; and Dustin is convinced that he has intercepted a secret Soviet spy transmission. Working as an intern reporter at the Hawkins Gazette, Mike's sister, Nancy, has rekindled her relationship with Will's brother, Jonathan, and together they have begun investigating a series of peculiar incidents. Their inquiries lead them to suspect Billy, who has started acting strangely. When Max and Eleven confront Billy at the local swimming pool, they realize he has been enslaved by the Mind Flayer. Meanwhile. Dustin shares the Russian transmission with Nancy's former boyfriend, Steve, and his sardonic workmate. Robin Buckley, at the Starcourt ice-cream parlor, only to realize that the source of the signal is beneath the mall itself. Accompanied by Lucas's whip-smart little sister, Erica, they uncover a secret base where Soviet scientists are working to reopen the inter-dimensional gate into the Upside Down. As a dark influence spreads through Hawkins, Eleven and the others find themselves facing not just an army of 'flayed' minions and a platoon of Russian soldiers, but the unearthly power of the Mind Flayer itself.