Here’s how Matt Duffer explained the major turning point in the history of Stranger Things:

The revelatory moment arrives during "Stranger Things" Season 5, Volume 2, when Dustin Henderson (Gaten Matarazzo) comes to the chilling realization that everything they thought they knew about the Upside Down has been "dead wrong.

Well, the wait is over. Today, on New Year's Eve, get ready to celebrate with Stranger Things' season 5 finale. Keep an eye on Netflix at 8 p.m. ET and 5 p.m. PT.

In Volume 2’s “The Bridge,” it is revealed that the Upside Down is actually part of a wormhole connecting Earth and The Abyss, another dimension occupied by Vecna ( Jamie Campbell Bower ), the Demogorgons, Mindflayer, and more.

Stranger Things has finally given a definitive answer about the Upside Down in Season 5 Volume 2. What once appeared to be a parallel dimension is now revealed to be something far more unstable and central to the show’s endgame.

After four-and-a-half seasons of questions prompted by “Stranger Things,” in Volume 2 of the show’s fifth and final season, creators Matt and Ross Duffer offered answers aplenty, while also setting up the potentially tragic stakes of the series finale.

Brenner’s notes explain that the Upside Down is a wormhole connecting Hawkins, Indiana to another dimension. Dustin dubs that world “the Abyss” because in D&D, it is “a realm of pure chaos and evil.” Image: Netflix Hopper (David Harbor) is less than enthusiastic about yet another D&D reference,

Stranger Things revealed the real origin of the Upside Down, and it flips a key element of the series on its head.

What if the finale of Stranger Things finale is not about winning the fight against Vecna, but about questioning the rules of the rigged game itself? With the last episode of the show looming around o