How ‘Stranger Things 5’ Finally Explains The Upside Down In Volume 2

SPOILER ALERT! This post contains details from Stranger Things 5 Volume 2.

After nearly a decade, Stranger Things fans finally have some answers about the Upside Down and the supernatural forces that have been plaguing Hawkins since Will Byers (Noah Schnapp) disappeared on November 6, 1983.

The second volume of the series’ final season unveils most of the secrets that creators Matt and Ross Duffer have been keeping from just about everyone since Season 1, including the fact that the Upside Down has actually been a wormhole to another dimension this entire time.

“We’ve known it was a wormhole since Season 1, but it’s one thing to say it, and it’s another to try to figure out how to visualize such an abstract concept,” Ross told Deadline.

The Wormhole

In the first two of three episodes, Nancy (Natalia Dyer), Jonathan (Charlie Heaton), Steve (Joe Keery) and Dustin (Gaten Matarazzo) are searching for clues about what could be behind the massive, flesh-like wall they’ve discovered surrounding the Upside Down-version of their town. They find answers inside Hawkins Lab, but not the ones they were expecting.

At the end of Episode 5, “Shock Jock,” Dustin discovers one of Dr. Brenner’s (Matthew Modine) journals at the same time that Nancy and Jonathan make it to the roof of the lab to find a mysterious presence floating above it. Dustin realizes far too late that neither Vecna (Jamie Campbell Bower) nor Holly (Nell Fisher) — nor anyone for that matter — are behind the wall, because the wall is actually holding the whole place together. Before he can warn Nancy and Jonathan, the older Wheeler aims her shotgun at the mass on the roof and sends a sweeping shockwave through the Upside Down, ripping a gash in the wall of the wormhole. It’s at that moment that viewers finally get a glimpse of what it looks like from afar.

“I think, ultimately, we really wanted it to have that hourglass shape, because we thought that was the simplest way to communicate such a big idea to the audience,” Ross explained. “But to do that, we had to zoom out. I can’t remember how many miles away visual effects figured out that we were by the end in order to see the full shape, but we had to go way out.”

“We’re very far [away],” Matt laughed.

Continued Ross: “Generally, we try to stay within the characters’ perspectives, but that was an instance where we thought to illustrate this best to the audience, we had to leave the characters’ perspectives for a moment, just to show the enormity of this whole thing.”

It’s thanks to Dustin that viewers, and the rest of the crew in Hawkins, won’t get lost in the theoretical physics of it all. After they make it out of the Upside Down, Dustin draws a diagram on the DJ booth at WSQK to illustrate what they’re up against. He explains that the mass that Nancy shot was exotic matter, and it’s the only thing keeping the wormhole intact.

“[The Duffers] literally drew that diagram at the season pitch out two years ago, because they understood, even then, that we would need visual aids,” Shawn Levy, who directed Episodes 6 and 7 with the brothers, said. “I’m so grateful that they had Dustin draw that exact same diagram in the show that the Duffers had used to explain the show years before we shot Season 5.”

The creators don’t credit themselves with devising that explanation though, nor with the flashlight and slinky that Steve uses to help the group understand how they might use the radio tower to get to the alternate dimension that Dustin has named “The Abyss.”

“One of our writers, Paul Dictor, his superpower is the harder sci-fi aspects of the show. He’s read every hard sci-fi book that there is,” Matt said. “As far as [when] it comes to this stuff, he’s smarter than Ross and I are, so he’s playing these things, and Ross and I are basically the Steve in the room going, ‘Huh?’ Illustrations help a lot. So we take a lot of those conversations that we have in the room and the way we help everybody understand it and map it onto the show.”

The Exotic Matter

Speaking of the exotic matter, as Nancy and Jonathan make their way toward the roof, they realize the entire building seems to be melting. Funnily enough, the melting lab was born not from any attachment to accuracy of an encounter with the theoretical sciences, but from a desire to put the characters in a life-threatening situation that may force them to have a conversation that they’d long been avoiding.

“All we knew was that we wanted the lab to be melting, and weirdly, actually, that idea came less because we thought it was cool, and more from it kind of all revolved around, or started with, that scene between Nancy and Jonathan. We knew we wanted to put them in a life-or-death situation,” Matt explained.

After Nancy shoots the exotic matter, the writhing ball of energy becomes even more ferocious, melting the top of the lab at a more rapid rate. She and Jonathan find themselves trapped inside a room as the roof melts around them, threatening to swallow them whole. It’s at that moment that Jonathan decides to come clean about the engagement ring he’s been carrying around this whole time.

Except, he doesn’t propose. Instead, he admits that he thinks maybe they aren’t meant to be after all, and he believes Nancy knows that deep down as well.

“One of the references was Almost Famous, just like a way less comedic moment than Almost Famous when they’re on the plane and they’re about to crash, and they all confess to this, because why not? You’re about to die. So we liked that moment. Titanic was a slight reference — they both now are able to fit on the table,” Matt revealed. “So we started from there and reverse engineered what would be a situation that would present that kind of moment for them, and we came up with a melting lab.”

Then comes the work of actually making the lab look like it’s melting, which required intense collaboration between the visual effects department, production designer Chris Trujillo, and art director Sean Brennan.

“It stressed everybody out,” Matt laughs. “Nobody liked the melting lab idea, not because [of] the concept, but no one actually wanted to do it.”

The final scene does include some computer-generated visual effects, although the Duffers lament “it was intended to be no visual effects.”

The production had developed a special “goo-like substance” to funnel into that room so that the scene was entirely practical. Unfortunately, when it came time to produce it at such a large scale, things did not pan out as intended, requiring some post-production magic.

“I think they tested it in too small of a batch, because by the time we had — I don’t know how many gallons of it that were needed to flood that room — it was much too thin. I mean, it wasn’t thick at all,” Matt recalled. “It was basically gray water, which was a big problem. So Nat and Charlie just acted it out [and] moved more slowly through it, and then we had ILM, who did a lot of visual effects on the final season, [adjust it]. I don’t know how they did it. They developed some sort of formula to fix it and make everything look thick. Obviously, they did all this incredible liquid simulation, at the end of the day. So it’s a real mix between practical and visual effects. It’s not, maybe, the showiest of our visual effects this season [but it] was one of the ones that blew us away.”

The Abyss…and Its Connection to Eleven

The wormhole, Dustin says, connects Hawkins to another dimension that he calls “The Abyss.” This is where be believes all of the monsters — the demogorgons, the Mind Flayer, Vecna — have all been coming from. It’s also why they haven’t been able to find Vecna in any of their crawls over the last two years. He’s not in the Upside Down at all. He’s actually thousands of yards above them, recovering in this alternate dimension, and that is where he’s keeping all those kids, including Holly. Those who have seen The First Shadow may draw connections to one Dimension X.

Volume 2 does give a glimpse at this other dimension, when Holly briefly escapes Vecna’s clutches and tries to make a run for it. Outside of his lair, the world looks barren and deserted, save for a few glowing red rifts in the ground where the world is connected to the Upside Down.

It’s certainly satisfying to get the answers about the Upside Down that have evaded audiences for so long, but, in some ways, all of these explanations come with a new set of questions. What is this alternate dimension? Why is Vecna so hellbent on merging it with the human world? Is this where Eleven (Millie Bobby Brown) sent him all those years ago?

The show has been alluding to the fact that the U.S. government’s been locked in some sort of arms race with Russia to access this alternate dimension, likely to use whatever lurks there as weapons of mass destruction. The Vol. 2 episodes also reveal that the government has once again started experimenting on babies in utero to create more supernatural humans like Eleven and Kali, using the latter’s blood. It hasn’t been working, though, which is why they’ve been after Eleven this whole time. They believe that her blood holds the key to creating more kids like her.

While the pieces are starting to fall into place, there are a couple of dots left to connect on this front, which the Duffers promise will happen in the two-hour finale.

“The goal is to tie up the remaining loose ends and answer any questions that remain,” Ross teases. “There are a few specifically big ones…Henry and his backstory, and then Eleven and what all this means for her and Kali.”

The Stranger Things finale arrives on December 31.