The sudden and mysterious disappearance of Will Byers and the appearance of a strange girl called Eleven become the beginning of a chain of events that will change how Will's family and friends see the world around them, and put them in danger in ways they could never have foreseen.
Nearly a year after Will's return and the defeat of the Demogorgon by a now missing Eleven, those affected by the events surrounding the Upside-Down are trying to go back to a normal life. But Will's increasingly terrifying visions of the parallel world herald the coming of a new danger... one that threatens the people Will loves.
In the summer of 1985 in Hawkins, the newly opened Starcourt Mall has become the focal point of the town, driving other stores out of business. After the horror of the last two years, our heroes are eager to move forward with new jobs, new friendships, and new romances. However, a mysterious radio broadcast and strange power fluctuations lead to the discovery of a new threat, while odd behavior by some of the town's residents causes a growing fear that despite having closed the portal to the Upside Down, they are all still in danger from it.