Just finished Volume 2 of Stranger Things Season 5 and have some questions? Saaaame.
There are several things that need to be resolved (that's what the finale is for!), but one lingering question? What was in the briefcase that Henry found in that mineshaft from his memories? As a reminder, Holly and Max witnessed a young Henry (in his pre-Vecna days) come across a wounded scientist clutching a briefcase—and after killing said scientist with a rock, we see Henry open the briefcase. Which is when some sort of smoke emerges.... So, what was it?
The Stranger Things play holds the answer to this question! As Deadline puts it, the briefcase "contains stolen technology from an experiment that accidentally sent a group of men to a place they’ve called Dimension X."
Turns out Dr. Brenner’s dad was part of the experiment, hence his obsession with Dimension X, Henry's powers, and the Upside Down. Meanwhile, the technology in the briefcase transported Henry to Dimension X and he, per Deadline, "returned with a unique blood type, a different personality and new powers."
In other words, that briefcase is the KEY to Henry's entire origin story, not to mention the plot of Stranger Things.
