The creators of Stranger Things know all about expectations. Ever since the series became one of the most successful shows in Netflix’s history—it was the most streamed program of 2022—every subsequent installment has had to try not to collapse under the heavy hopes of millions of fans. Anticipation for the first official Stranger Things stage production is similarly through the roof. Rarely has a theater seen such an ardent base rock up, demanding to be entertained.

The venue is London’s 1,028-seat Phoenix Theatre. (If you wanted to bring all of the adults who watched the first season within its first 35 days to see the play, it would need to be staged roughly 13,687 times.) Stranger Things: The First Shadow follows two comedies recently staged there: the beloved British farce Noises Off and the comedy puppet show Spitting Image: The Musical. “We chose a very small theater to do our very big play in,” says codirector Justin Martin, speaking from the snug “company office,” where a shower is visible behind him.

Olivier Award–winning director Stephen Daldry was the man with the provocative idea to bring Stranger Things, conceived by brothers Matt and Ross Duffer, to the stage. Around the time the fourth season was being written, Daldry teamed up with producer colossus Sonia Friedman to approach Netflix about what Martin calls its “catalog.” “The Duffers, to their credit, went, ‘You’re mad, but yeah, let’s see if we can find something within this world,’” says Martin, who has worked with Daldry for 16 years. “The honest truth is, the idea of turning the show into a play would’ve never crossed our minds,” the Duffers say by email. “This is fully the brainchild of Stephen Daldry.”

Producer Friedman and writer Jack Thorne, who are responsible for the mammoth theatrical success of Harry Potter and the Cursed Child, were a reassuring presence. But First Shadow was complex territory. “The cycle of Potter was complete, and therefore we had access to the full canon [for Cursed Child],” Friedman says. She can’t think of another live show emerging mid-canon like this. Arriving while we wait for the series’ season five (its strike-delayed filming is due to start next month), First Shadow takes place before the first season, in 1959, and explores the high school past of Henry Creel, dramatizing how he became the murderous Vecna we meet in season four.

“The mythology is quite complicated,” says Friedman, speaking in the sing-song style of someone who has just stumbled on an r/StrangerThings Reddit thread. Thorne bowed out after one draft, passing the baton to Kate Trefry, who has written for Stranger Things since season two. “It’s just like a huge jellyfish of interlocking pieces,” Trefry says. “We wanted to hit this sweet spot where the play can stand on its own as an independent work but also connect to everything in four, but also be looking forward to five.” We meet younger versions of Joyce Byers, née Maldonado (Isabella Pappas), Jim Hopper (Oscar Lloyd), and Bob Newby (Christopher Buckley), who investigate some neighborhood pet deaths; we also meet Dr. Brenner (Patrick Vaill) and come to understand why he began his horrifying experimentation on Eleven and other children.

First Shadow is visually stunning and could easily make stars of its young cast, principally Louis McCartney, who plays Henry, and Ella Karuna Williams, who portrays new character Patty Newby. Martin says that they told casting director Jessica Ronane, “We want to find the next Ben Whishaw and Andrew Garfield.” The real star of the show, however, may be the often jaw-dropping stagecraft. The program claims that First Shadow is “the most technically advanced show in the West End,” an assertion that’s hard to test but easy to believe.

Chris Fisher and Jamie Harrison, who head up the illusions and visual effects team, took a trip to Vegas to see how the world’s biggest magicians pull it off. “When you’ve got a show of this scale and a show of this budget as well, you can really push the boundaries,” says Harrison.

Fisher, who has worked with Harrison on shows like Cursed Child, is also a magician and a member of the elite group the Magic Circle; he’s used to pulling the wool over people’s eyes. When writing, Trefry was asked not to worry about the limitations of the stage but to deliver something akin to a Stranger Things film. With the help of holograms, projections, and a revolving stage, a theatrical language was developed to bridge the gap between screen and stage. Members of the audience look aghast at one another when a character disappears or an entire set seems to have been conjured out of thin air. While actors hold the audience’s attention, backstage there are hundreds of people frantically preparing the next set piece. “People just don’t realize how long it takes to get those things slick and smooth,” says Harrison.

In bringing Stranger Things to the stage, Daldry and Martin wanted to genuinely scare their audience. They seem to have succeeded, with many moments far more frightening than anything on Netflix. “What we love about the play is that it is able to do things that the show simply can’t,” say the Duffers. Friedman and company hope the show’s success may even revitalize an industry that has wavered and wobbled through the challenges of the pandemic. “Young, new audiences are flocking to see it,” says Friedman. “And they are genuinely new. For many of them, it’s their first time in [a] theater.” The thrill of the medium, says Friedman, is that it’s “high-wire stuff”—constantly evolving, never complete. “It’s not for everybody. But for those who commit and suspend their disbelief for two or three hours and go for it, it can be life-changing.”

Will First Shadow set a precedent for other Netflix transfers to the stage? Is it just a matter of time until we see Squid Game: The Musical or The Crown: The First Corgi? Deep in previews and two weeks before the show opens to the press, Friedman isn’t saying yes—but she’s not saying no, either: “I think you should probably ask me that in about six weeks’ time.”