If you hadn’t seen Netflix’s runaway genre hit Stranger Things and were asked to imagine a place creepy enough to house a rift into a world of monsters and misery, you’d need a severely damaged psyche to conjure anything quite as troubling as Building A of the former Georgia Mental Health Institute in Atlanta.

Viewed from the air, the building’s brutalist concrete boxes form a crucifix; on the inside, windows peer through a concrete latticework that evokes a prison more than a hospital. When it was in active use from the mid-’60s, housing adults, children and “the criminally insane”, a series of underground tunnels connected Building A to various residences. The residences have since fallen into disrepair, and not even the most naïve victim of a schlocky horror movie would be clueless enough to venture down these tunnels.

Simply put, Building A is a production designer’s wet dream. So, of course, it became the site of the fictional Hawkins Lab in Stranger Things, where Matthew Modine’s Dr. Martin Brenner experimented on caged test subjects in an attempt to harness latent psychokinetic abilities. If that kind of pseudoscientific insanity goes on anywhere, it goes on in a place like this.

On a gray spring day in Atlanta, the cast and crew of Stranger Things have assembled once more inside this macabre asylum. Bloodied corpses litter the ground, and a newcomer to the Stranger Things cast, Sean Astin, shines a flashlight over them. With a nervous energy befitting a man condemned to traverse a passageway of the dead, he pushes his way onward. “OK, cut,” yells a voice. And with that, the cadavers rise, stretch their tired limbs back to life, and head to craft services to pour themselves cups of coffee.

It’s not surprising that the show has returned to Hawkins Lab for Season 2. It was, after all, the catalyst for Season 1’s contained narrative about a group of Dungeons & Dragons-playing preteens and their families, whose lives are rocked when their friend Will goes missing one night. While the boy’s frantic mother Joyce (Winona Ryder) starts searching for her lost son, and the town’s world-weary police chief Hopper (David Harbour) is dragged into an investigation he hasn’t the patience for, the three remaining friends stumble upon a feral mute girl who may hold the answers to Will’s disappearance.

Set in an eerily authentic 1980s world, the show pulsed with an electronic score and channeled Stephen King and Steven Spielberg so authentically, it was as though they’d written it themselves, and left it in a drawer for 30 years.

In fact, it was the brainchild of Matt and Ross Duffer, 33-year-old identical twin brothers who had been preteens themselves when they first alighted on the pop culture of the’80s. Both served on the writing staff for the M. Night Shyamalan-produced series Wayward Pines, and had written and directed a little-seen horror film called Hidden in 2015, but Netflix had boarded Stranger Things that same year with little concern for their relative inexperience. “At the time they took the show,” says Ross, “they were used to working with a slightly higher caliber of showrunner. But I think they were ready to start taking more chances.”

“Sometimes I ask them why they let us do it,” says Matt, who can be distinguished from his brother by a small shock of gray hair above his forehead. “They say they think they get better results when they have the people that are the most passionate in charge.”

Passion flows from the Duffer brothers. In the time they make for Deadline, while they’re juggling a highly complex shoot directing the penultimate episode of Season 2 (other directors this year include Stranger Things newcomers Andrew Stanton and Rebecca Thomas, as well as core creative EP Shawn Levy), they frequently veer off into reveries about the pop culture of their youths. Astin is just the latest star of the ’80s they’ve cast in Stranger Things, further cementing the show’s uncanny channeling of the decade that other retro projects have summarily failed to capture. As well as Matthew Modine, who starred in a string of ’80s hits, the first season of the show cast Winona Ryder, who made her big-screen debut in Lucas in 1986, while Season 2 also adds Paul Reiser, of Beverly Hills Cop and Aliens fame.

“It gets bigger and bigger, this season,” says Ross. An already released teaser reveals that the episode they’re shooting today is called “The Brain”, but the Duffer brothers will elaborate no further on the specifics. “It’s even more intense,” Ross allows. “But it’s interesting because we get to spend some time with our characters when they’re not worried about their lost friend. We get to see some other sides to them upfront.”

The first, eight-episode season of Stranger Things went live on July 15th 2016, turning the many newcomers in its cast into instant household names, and cementing the careers of even its more established players. In as long as it took to watch all eight episodes—in other words, less than a day—Stranger Things became the year’s most talked-about new show. “It seemed to happen fast,” says Matt. “We kind of thought it would have more of a niche appeal. When you pitch it in a room, you say, ‘Oh, it’ll have adults, teens and kids, so it’ll hit all those generations.’ But we didn’t really think that would work.”

There was a Stranger Things for every audience. For adults who had grown up on the music, genre movies and books of the 1980s—as the Duffer brothers had—it was a trip down memory lane. But even for kids and teenagers, who had no knowledge of its references, the show worked on its own terms.

Like many kids, Noah Schnapp was away at summer camp when Stranger Things premiered. It was his character, Will Byers, who went missing in the first episode of the season, kidnapped by “Demogorgon”, as the boys had nicknamed it, a terrifying monster that had come from the Hawkins Lab rift into an “Upside Down” realm full of decay and death. We saw precious little of Will after that—except in flashback form—as his friends worked tirelessly to figure out what had happened to him.

Still, Schnapp missed out on none of the fervor that greeted Stranger Things’ launch, even if he did have to catch up on it when he returned from camp. “My mom was telling me all the stuff that was happening with it,” he recalls. “It wasn’t until I came back from camp that I started getting recognized. It still feels weird. In the show, I have a bowl cut, and when I’m out of the show I usually have my hair up or something, but people still recognize me.”

All of the show’s younger cast members share similar stories, and the Duffer brothers can’t easily fathom why their show had such instant appeal. “We were really just trying to ask ourselves what kind of show we’d want to watch,” notes Ross. “If we could watch anything, what would it be? We knew we were appealing to the people of our generation who were nostalgic for this type of stuff, but it’s exciting that it reached 12-year-olds out there. We were that age when we were discovering these films and books that influenced us.”

“And by the way,” notes Matt, “most 12-year-olds today aren’t even aware of them.”

Finn Wolfhard would be the first to disagree. He was, admittedly, 13 when he was cast as Mike Wheeler in Stranger Things. But he was already an aficionado of the pop culture of an era that had ended more than a decade before he was born. “Me and Millie and Gaten had seen loads of ’80s movies,” he protests, referring to his similarly youthful co-stars Millie Bobby Brown and Gaten Matarazzo. “In fact, I think there was a movie Gaten had seen that even I hadn’t. Firestarter.”

“Finn is a bonafide movie buff,” concedes Matt. “When we first met him, he was like, ‘Oh, I’m into early Sam Raimi.’ I was like, ‘What?’”

In fact, as Astin went for another take downstairs, Wolfhard confessed he’d already quizzed his new co-star at length about his ’80s-era filmography (and if you want to feel really old: even Astin’s turn as Sam in Peter Jackson’s Lord of the Rings trilogy was two-thirds done by the time Wolfhard was born). “They were showing The Goonies [on set] the other day,” he recalls. “It was really funny to see Sean with braces as a kid, because he plays sort of a father figure for our group. I’ve asked him any and everything I could about that. He’s like an open book.”

“Goonies, Stand by Me, E.T., I’ve seen them all,” says Brown, who plays the mysterious Eleven in the show. “And Finn has too, so I think when we got the job we were both like, ‘Oh, we know what to do.’”

Brown had screen-tested with Wolfhard for a show that was, once, called (and set in) Montauk. It changed to Stranger Things when the production set up shop in Georgia, which doesn’t match very well for the East Coast. The location then switched to the fictional town of Hawkins, Indiana. “But we didn’t want to do the Eerie, Indiana or Twin Peaks thing and name it after a fictional place,” says Matt, “because it had been done a lot.”

“At my screen test was one boy, one girl and Finn,” recalls Brown. “I went in and was with this other boy, and then the other boy left and Finn came in. Immediately it felt right.”

“Acting-wise, we clicked,” echoes Wolfhard. “And we’ve all become a family now.” The script for Montauk, he notes, morphed into Stranger Things as each of his co-stars was cast. “Gaten’s character, Dustin, was originally supposed to be this self-conscious fat kid,” Wolfhard says. “When Gaten auditioned, Matt and Ross completely changed it around and realized he should be the powerhouse of the group, keeping everyone together. We all add little bits of ourselves. With Noah, his character, Will, is him, but he’s heightening his shy side. Caleb [McLaughlin]’s sensible, adult sort of vibe got put into his character.”

As for how much of Finn is in Mike, “I guess if I ever was a leader, I’d say that side comes from me—Mike’s confidence,” Wolfhard muses.

The Stranger Things cast shared the SAG Ensemble Award in January. “And it was one of the best moments of my life,” says Schnapp. “I’ve never really cried tears of joy, but I was getting teary.”

On the SAG stage, his grown-up co-star David Harbour delivered an impassioned anti-Trump speech that made international headlines. It was “my attempt to make people feel not alone,” he would say later. It came from the heart and was delivered in a moment of heightened emotion as this family was honored with its first major acting prize, together.

“It was just so surreal,” remembers Caleb McLaughlin, who plays Lucas. “We weren’t expecting to win because we had such great competition. When we heard the word ‘Stranger’, we stood right up. We didn’t even need to hear ‘Things’. What really took it to another level is when they said we each get to have our own SAG Award.”

“I didn’t know they’d do that,” laughs Schnapp. “After the backstage interviews they brought us into this room and there was a line of awards with our names on them. I grabbed it to my chest the rest of the night.”

In a filmmaking hub like Atlanta, nobody bats much of an eyelid when a film unit sets up next door. On the way to the Stranger Things set from downtown, several different unit signs point to the various shoots around town. But with the tremendous love this show has had from audiences, critics and awards shows, it’s now hard to miss the Stranger Things roadshow, and so security has, inevitably, tightened.

“But we’re still that little show in Atlanta that’s filming,” insists Brown. “We all came back here and remembered being here on day one of Season 1, so we never think, ‘This show is too good to fail.’ We could have all been extremely big-headed, but we’re not. We’re all just really happy to be together and doing it all over again.”

“It feels like we’ve never left,” adds McLaughlin. “When we all first met, it was so quick. We all have big personalities, we all love to talk to each other, and so it was easy to get to know each other and have fun actually being kids.”

“There’s a lot more trust now, especially after Season 1,” says Matt of the Duffers’ relationship with their actors, young and not-so-young. “We trust them with their characters and they trust us a lot with the writing—if something feels wrong to them, they let us know. So much of this show was in the casting. It’s like 90 percent casting. You want to stay away from them. You cast them, and let them do their thing, ’cause they’re better at it than we are.”

The Duffer brothers are reluctant to say that they have a rock solid strategy for where Stranger Things goes from here.

“You have a grand plan, but then you discover so much cool stuff on the day,” argues Matt. “But I feel like we tend to have guard rails set up, because we do know generally where we want to go. And then you get to play inside that.”

“We’ve learned not to fight it as much,” admits Ross. “That you had this plan for where this character was going, and then you get here and you’re like, ‘Whoa, I don’t believe in it anymore.’” There is, though, an end goal in sight. “We have a blinking light that we’re headed toward.”

For the many fan speculators on the internet—the Duffers and the cast say that all the secrets of Season 2 have already been untangled by fans, albeit by accident, and hidden amongst reams of incorrect guesses—one popular Season 1 character just won’t die. Shannon Purser’s Barb was, herself, kidnapped by the Demogorgon, and though there was a pretty clear coda about her unfortunate fate towards the end of the season, many believe she hasn’t disappeared forever.

So is that the Duffers’ final image? “Yeah,” laughs Ross. “It’s going to be Barb’s hand reaching out from the grave. Cut to black.”