After keeping us in the dark for nearly 10 years, Stranger Things has finally revealed what the Upside Down is. In fact there is – and as Dustin Henderson says in season five, all our theories about the dark kingdom so far have been “completely wrong.”
Well, if you haven't seen the play Stranger Things: The First Shadow, that is…
It was there that he was trapped for four years until Eleven made remote contact with the Demogorgon – and an inverted tunnel was formed. Since then, Henry/Odin/Vecna has been using the Upside Down as an entrance to the real world, creating a gateway in an attempt to destabilize it and ultimately unite the Void with Hawkins. In short, the big bad wants to turn Earth into his own monster-filled hell.
“Netflix wanted us to explain the mythology to them because we were very adamant from the beginning: 'We don't want to explain it in the show. We love that there's a mystery and that by the end of the season there's a lot that you don't understand,” Matt Duffer recently explained to the publication Diversity. “They said, 'That's fine, but we'd like to know.' I think it was actually a really good exercise – we spent a lot of time with our writers figuring out what exactly Upside Down was.
“We wrote a 20-page mythological document. At that time it was not called “The Abyss”, it was called “Dimension X”, which is a reference to “Teenage Mutant Ninja Turtles”. We've held these cards for so long; it was a real relief to see my hands here.”
If you've been lucky enough to see The First Shadow, you've probably heard of Dimension X before. The play, which explores Henry's backstory, begins with a prologue set in 1943, in which a warship called the Eldridge is sucked into Dimension X. This ship has been captured by Captain Brenner, Martin's father and the only survivor of an otherworldly disaster; his crew members were killed by evil smoke creatures.
Although it does not mention the fact that Joyce and Hopper went to school with Henry, it is a major plot point of the play and something that was hinted at throughout the volume. 1, Vol. 2 featured another moment for which stage show goers will have a little more context. While exploring Vecna's Mind Lair, Max and Holly recall his worst memories and see young Henry in his Boy Scout uniform encountering a bloodied Soviet spy inside the mine.
Horrified, the spy shoots Henry in the arm, resulting in the boy fatally bludgeoning the older man with a rock and pinching the metal briefcase he stole from the US Army. The play explains that a dazed Henry, missing for 12 days, was found with a wound to his arm near a cave system in Nevada. It also clarifies that the Russian was found dead inside caves a little later. While the Netflix show doesn't reveal what's in the briefcase, those who have seen the play know that it contains useful tips regarding Dimension X and other top-secret technologies.
The play establishes that the contents of the briefcase transported Henry to Dimension X, leading to his first encounter with the brain-breaking Mind Flayer. Some time later, Dr. Brenner connected the dots between Henry and the Mind Flayer by finding the former's spyglass in the caves, the one Holly used in the TV show.
Stranger Things Season 5 Vol. 1 and vol. 2 is currently streaming. Don't miss the finale with our guide to Stranger Things season 5 release schedule. If you need help figuring out what exactly has happened so far, check out our breakdown Stranger Things Season 5 Vol. 2 ending explained.
