As the new season of Stranger Things begins in Chapter One: The Hellfire Club, we find the characters from Hawkins engaged in the same revelries and pursuits as before — until new visitors arrive at the Science Museum to disrupt the peace. The episode opens with a group of young people sneaking into the Russian surveillance room, the monitor room for the monstrous Mind Flayer that the Hawkins crew fought and vanquished in Season 3.

Meanwhile, Eleven continues to struggle with a lack of control over her powers — she can no longer levitate or use her telekinetic abilities. As she and Mike are celebrating a year of going steady after the end of Season 3, they and the rest of their friends notice that they are being followed by a crew of dangerous looking punks on motorcycles.

Later, they visit the Hawkins Science Museum, where Dustin and Lucas are taking part in the ceremony of opening the Bauman Bunker, a time capsule composed of objects from 1985 that will be opened 50 years later. However, they quickly notice that something is amiss when they see a shady-looking man wearing a Soviet uniform in a corner. The episode closes with the kids hearing a terrifying groaning noise from deep underground, hinting at the mystery and danger that awaits them as the new season continues.

Chapter One: The Hellfire Club sets the stage for the new season of Stranger Things, with a perfect blend of science fiction and horror elements that have come to be a hallmark of this beloved series. The episode introduces new characters and threats, while continuing to develop the relationships and personalities of our familiar friends. It leaves the audience intrigued and eager to plunge further into the world of Hawkins and its many secrets beyond.