Stranger Things 5 Will Finally Solve The Show's Longest-Running Mystery

Spoilers ahead for season 4 of "Stranger Things."

"Stranger Things" season 4 solved some mysteries for fans after years of waiting. We learned about Eleven's (Millie Bobby Brown) history in Hawkins Lab and how things went awry. We saw that love between friends and romantic partners can save the day, and that listening to a favorite song can block you from Vecna (Jamie Campbell Bower). (We also learned that if you use a song like Kate Bush's "Running Up That Hill" or Metallica's "Master of Puppets," those artists will get a boost on the charts.) Most importantly, we learned that Henry Creel became an orderly at Hawkins Lab, but was also the first patient, 001, and after revealing himself to be evil and killing the other patients, Eleven burned him, ripped open a portal to the Upside Down, and Creel became the monster Vecna, who is terrorizing Hawkins.

However, there are still a few mysteries left to solve. According to a Duffer brothers interview with Collider, one of the biggest questions that fans still have will be answered in season 5 of the Netflix series. (Well, the biggest after "When are we going to see Will actually admit his feelings for Mike in a way that isn't veiled?")

In the interview, Ross Duffer explained that while the show pulled back the curtain on a few big reveals in volume 2 of the fourth season (the epically long episodes 8 and 9), those were more about Henry and Vecna than anything else. "But what we haven't really discussed is exactly what the Upside Down is," he said.

The origins and exact nature of the Upside Down have been a mystery since Will Byers (Noah Schnapp) was first taken there in the very first season. Did Eleven create it? I think that's unlikely. For me, it seems that she just opened a door to another dimension or universe. The multiverse is all the rage these days, and this is sort of a hop, skip, and a jump from that. 

We know that the Upside Down — the part that we've seen, anyway – is a different version of Hawkins, but frozen in time on the night in 1983 that Will disappeared. We know its inhabitants include the Mind Flayer, the Shadow Monster, the Demogorgon, Demodogs, and some crazy bat creatures. We know the bodies of those who were taken (like poor Barb) are still trapped there. We know from Vecna's speech at the end of season 4 that he was sent there and discovered the Mind Flayer, and that, like Will did later, he'd been drawing that creature for years. Did he conjure that with his own mind? Was it already there to begin with? How exactly did Russia get involved?

Ross Duffer said of the mystery, "The big reveals that are coming in Season 5 are really about the Upside Down itself, which we only start to hint at. There is that moment where we realize in episode 7 this year that it's frozen in time." 

The site revealed that the Duffers have said Will will "be a big part" of the fifth season, which is a good thing, as it feels like his story has gotten sidelined a bit. It's been all about Eleven's connection to the Upside Down, but Will was the one who was taken there. What did Vecna want with Will? Was there something else down there? Ross Duffer also provided questions that he says will be answered in season 5. "What was that where Henry was when he was found? The Mind Flayer, where is that?"

It was recently revealed that there will be a time jump for season 5, though that does leave even more questions. Is Vecna healing down there? And for how long? Season 4 ends with all of Hawkins cracked into quarters, and the town believes it was an earthquake, with some of them ascribing it all to a Satanic cult started by the Dungeons & Dragons group the Hellfire Club, headed by Eddie (Joseph Quinn), who was a perfect metal-loving joy. Rest in peace, Eddie.

It will be interesting to see how this all concludes, since season 5 will be the final season. I do wonder if they just close the portal, leaving it vulnerable to being opened again by someone else with powers, or if they have to destroy the entire thing to take down Vecna and his monster friends. Will Eleven and Will have to work together to destroy it all? 

"Stranger Things" season 4 is currently streaming on Netflix.