What Is The Upside Down? Stranger Things Season 5 Volume 2 Reveals The Truth

Contains spoilers for "Stranger Things" Season 5 Episode 7 — "The Bridge"

For the entire run of "Stranger Things" thus far, we've become intimately familiar with the Upside Down, the mysterious and shadowy realm that lies underneath the fictional and supernaturally tormented Midwestern town of Hawkins, Indiana. Ever since Will Byers (Noah Schnapp) was kidnapped and brought to the Upside Down in the show's inaugural season, which aired back in 2016, the undergroud hellscape became a part of pop culture history. Now, we know the real truth about the Upside Down — and if you haven't watched through "Chapter 7: The Bridge," you'll want to turn back now, because spoilers lie ahead!

The Upside Down is less of an alternate realm and more of a bridge between, as Dustin Henderson (Gaten Matarazzo) reveals, "space and time." See, in the final season's sixth episode "Escape from Camazotz," Dustin reveals to Steve Harrington (Joe Keery) that he's discovered journals belonging to Dr. Martin Brenner (Matthew Modine), the original father figure to Millie Bobby Brown's Eleven who once ran Hawkins Laboratory. According to those journals, the Upside Down isn't a proper realm, but a bridge that's allowing Vecna (otherwise known as Henry Creek or Mr. Whatsit, played in all forms by Jamie Campbell Bower) to travel between Hawkins and a larger world full of evil creatures. Not only that, but Dustin realizes that Vecna didn't create the Upside Down as the gang previously assumed; the villain simply uses it to keep trying to take over Hawkins and destroy the town. Dustin, as it happens, seems to have largely cracked the case on what exactly is going on with the Upside Down, and his expertise might even help the gang defeat Vecna once and for all.

If you're a regular Dungeons & Dragons player, you might know that Dustin's term "The Abyss" isn't exactly original; in D&D, the Abyss is the plane of existence from which all evil is born (and is classified, within the game's famous system, as "chaotic evil"). It's also the home of demons, so it makes a ton of sense that the Duffer Brothers would incorporate this into the final season of "Stranger Things."

So how does Dustin explain what's going on here? Let's look at his own words, which are part of a rousing speech he delivers to the whole gang:

"We've always assumed the Upside Down was another dimension opened by Brenner, but it turns out it's actually a bridge. More specifically, an interdimensional bridge that rips through space-time. It is wildly unstable but held together by exotic matter, which we found, dead center, right above the lab. In theoretical physics, they call this type of bridge a wormhole. And this wormhole connects Hawkins to here — another world, that I've coined the Abyss!"

This, obviously, changes almost everything we all thought we knew about the entire conceit of "Stranger Things." If the Upside Down we've been seeing — the one that seems to strangely mimic the Hawkins above it — is nothing more than a passageway to something even more horrifying, it stands to reason that our central gang of Vecna fighters have their work cut out for them. Plus, the Abyss, unlike the Upside Down, isn't under anything; it's thousands of feet above the ground. Thankfully, Dustin seems to have a solution.

As Dustin continues to explain, he believes that the Abyss isn't just "the true home of the Demogorgons, the vines, the Mind Flayer, [and] all the nasty sh*t from the Upside Down," but in the moment where a young Eleven banished Henry Creel to an unknown realm, she sent him to the Abyss. Thanks to Dr. Brenner's work with Eleven, she inadvertently "made contact with the Abyss" and, according to Dustin, "a bridge formed." This, as Dustin puts it, is precisely how Henry, also known as Vecna, is able to constantly invade Hawkins without much of an issue: "Henry and his monsters have been using it to cross right back into Hawkins. We kicked Vecna's ass last year but he just fled across this bridge."

What does this mean for the fate of the Upside Down and our intrepid gang? Well, Dustin makes it clear that they can't just blow up the Upside Down itself because then they'd blow up this bridge and fall right along with it; instead, as Vecna continues to "move" children out of Hawkins by making more and more rifts in the abyss, Steve comes up with an idea. Basically, they'll draw Vecna closer and closer to the Abyss and blow that up with a makeshift bomb as they all escape the Upside Down together, getting rid of this dangerous bridge once and for all.

Will it work? We'll have to wait and see when the series finale of "Stranger Things" drops. The last episode of the hit Netflix series will air on the streamer on December 31.