Throughout the captivating journey of “Stranger Things,” viewers have been drawn into the eerie and enigmatic world known as the Upside Down. This shadowy dimension has haunted the fictional town of Hawkins, Indiana, ever since young Will Byers (Noah Schnapp) was abducted in the show’s 2016 debut. As the series has unfolded, the Upside Down has cemented its place in pop culture lore. Now, with the revelations from “Chapter 7: The Bridge,” a new understanding of this mysterious place emerges. If you haven’t caught up yet, proceed with caution, as significant spoilers await!

In a surprising twist, the Upside Down is unveiled not as a mere alternate dimension but as a conduit between “space and time,” a discovery made by the ever-curious Dustin Henderson (Gaten Matarazzo). During the show’s sixth episode of the final season, “Escape from Camazotz,” Dustin shares a revelation with Steve Harrington (Joe Keery) after uncovering journals belonging to Dr. Martin Brenner (Matthew Modine). Dr. Brenner, once a pivotal figure to Eleven (Millie Bobby Brown) at Hawkins Laboratory, documented that the Upside Down serves as a bridge, facilitating Vecna’s (a.k.a. Henry Creek or Mr. Whatsit, portrayed by Jamie Campbell Bower) travels between Hawkins and a larger universe teeming with malevolent creatures. Contrary to previous beliefs, Vecna did not create the Upside Down; instead, he exploits it in his relentless quest to conquer Hawkins. Dustin’s breakthrough might just be the key to thwarting Vecna’s sinister plans.

If you’re familiar with Dungeons & Dragons, Dustin’s reference to “The Abyss” might strike a chord. In the world of D&D, the Abyss is a chaotic evil plane, teeming with demons and the birthplace of all that is wicked. The Duffer Brothers’ decision to weave this concept into the final season of “Stranger Things” adds a rich layer of depth to the narrative.

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.