What's Inside The Briefcase Henry/Vecna Finds In Stranger Things Season 5?

The following article contains spoilers for "Stranger Things" season 5, volume 2. 

There have been quite a few mysteries in the "Stranger Things" timeline, but season 5, volume 2 has one mystery that fans need extra help to figure out. While trapped inside the villainous Vecna's (Jamie Campbell Bower) mind prison, Max (Sadie Sink) and Holly (Nell Fisher) see a much younger version of Vecna when he was still just a human child named Henry Creel. Holly watches Vecna's memory of himself as he finds a wounded scientist and then kills him with a rock before taking the man's briefcase. When he opens it, smoke begins to pour out, but Max comes to save Holly before we get to see what happens next. There's not really much other mention of it, but clearly, that briefcase is important. So, uh, what the heck? 

The answers are contained within the "Stranger Things" prequel stage play, "Stranger Things: The First Shadow," which premiered in London back in 2023. In the play, we learn that young Henry found and opened a briefcase that transported him to Dimension X, where he was infected by Mind Flayer particles, forever changing his DNA. Since Vecna is the big bad of "Stranger Things," revealing his origin story in a stage play and only hinting at it on the actual streaming series seems kind of silly. The show has told us that he's the original super-powered being in our dimension and has even explained how his blood was used to create the other psychic kids, but leaving out his origin is a bit odd. Indeed, season 5, volume 2 has been a bit frustrating overall, and choices like this definitely contribute to the problem. 

The briefcase serves as the mechanism for Henry to travel to Dimension X and become infected by the Mind Flayer, leading to the eventual creation of the wormhole that is the Upside Down, but absolutely none of this is explained in "Stranger Things." Instead, it's all laid out in "Stranger Things: The First Shadow," which adds even more lore to the already dense "Stranger Things" compendium. Having a spin-off stage play is fine, but making it required knowledge in order to fully appreciate "Stranger Things" is some serious horse hockey. People just want to see what happens to their favorite characters, and adding more and more confusing lore and expecting everyone to pick apart the puzzle box is deeply irritating.

In "The First Shadow," we learn that the briefcase is stolen technology that accidentally transported some men to Dimension X and that Dr. Brenner's (Matthew Modine) father was a part of that experiment, which is what made Dr. Brenner so obsessed with Dimension X and creating Eleven (Millie Bobby Brown) and the other telekinetic children. This was all done by injecting pregnant women with Henry's blood, infecting the newborns with Mind Flayer particles. This all feels pretty darn important, so why was it only revealed in full in the stage play? Much like the adult actors still playing the kids on "Stranger Things," I am too old to be doing homework, especially when it's for something that's supposed to be entertainment.

"Stranger Things" season 5 will conclude on December 31, 2025, on Netflix.