Fast forward to: 1983
After opening an interdimensional gate and inadvertently letting a monstrous creature loose, test subject Eleven escapes into the woods of Hawkins, Indiana from Hawkins National Laboratory, with Dr. Martin Brenner and his agents looking for her. Meanwhile, the monster, the Demogorgon, kidnaps Will Byers.
The next morning, Joyce, Will's mother, realizes her son is missing, and rushes to the police station to meet with Chief Calvin Powell. After listening to Joyce, Powell is indifferent and assures Joyce that he is just fooling around. Even after two days of Will being missing, Powell does nothing to find Will, nor does he do anything when Barbara Holland also goes missing suspiciously. Meanwhile, Will's friend Mike Wheeler searches for him and comes across Eleven, whom he takes to his house. Joyce communicates with Will through Christmas lights, and encounters the Demogorgon, while Mike and Eleven evade Dr. Brenner. Will's brother Jonathan and Barb's best friend Nancy join forces to kill the Demogorgon. Eleven finally kills the Demogorgon at Hawkins Middle by banishing it to the Upside Down, herself being transported there in the process. Eleven comes back, but runs away from Mike's house when she sees agents. She lives in the forest of Hawkins until she becomes feral and deranged. Joyce finally goes to the Upside Down through the gate at Hawkins Middle, but it's too late, Will is dead.
The next year, the leader of the Upside Down, the Mind Flayer, sends adolescent Demogorgons called Demodogs to Hawkins. They massacre a significant portion of the town, until the Mind Flayer sends a full-fledged army of Demogorgons and Demodogs to take over the world under former test subject Henry Creel's command.
