The Contents of that Briefcase Henry Opens in the Hit Series?
For much of the concluding season of the popular Netflix show, the young Holly Wheeler and Max find themselves trapped within a psychic prison constructed from the past of the villain Henry. Their mission for a way out in episode 6 leads them to experience a traumatic incident from Henry's childhood—an event that may just hold the key to defeating him permanently.
Heads Up: This discussion details significant events for the concluding episodes.
Unearthing the Secrets of the Tunnel
When she finds Max in the mental landscape known as Camazotz, it becomes clear she is taking refuge in a chamber that Henry strangely fears. An accidental discovery a spyglass found in Henry's old home lets Holly see that the danger lies not within the cave. Matching her view with the shape, she and Max suddenly fall into a deep mine shaft.
They watch a Henry as a boy come across an injured and paranoid man. As the boy offers aid, the man panics and shoots, striking Henry in the hand. In a desperate act of self-defense, Henry kills the man with a rock. "Did this make Henry evil?" Holly asks tearfully. It was a factor, but the event went deeper than a defensive killing.
Like many elements of the final season, the significance of the mine shaft incident is detailed in the theatrical production Stranger Things: The First Shadow.
A Naval Mystery and Stolen Research
This backstory explains the infamous Philadelphia Experiment, which transported a vessel into a dimension dubbed the Abyss. It faced creatures, and the lone returnee was the ship's commander, who came back in a catatonic condition with an different blood composition.
That survivor's offspring, a young Martin Brenner, wanted to repeat this phenomenon in remote Nevada. But a disloyal lab worker stole research materials to sell to the Russian agents, who were desperate to launch their own interdimensional projects. This spy in the mine shaft was that very thief.
So, What's in the Case?
Based on what is understood of Brenner's work, the container would assuredly have some of the altered blood. At that moment, Henry is wounded and bleeding. He likely becomes contaminated upon contact with the blood, which triggered the development of his psychic abilities—abilities he would later pass on to the test subjects under Brenner's care.
Alternatively, the case could have held dark matter that later made its way to the Hawkins lab, where it acts to anchor the mirror dimension. The prequel shows that the boy somehow wound up in the Abyss, returning after half a day as a different person. From then on, he fights the whispers of a sinister presence, reminiscent of how Will Byers was possessed by the shadow monster in season 2.
Confronting Terror
Henry's enduring terror linked to that memory highlights how utterly horrifying the event was for him. While he commands the collective consciousness and attempts to pull the Abyss into Hawkins, a piece of the scared boy lingers. The villain weaponizes terror, and the show is setting up a final confrontation between him and Will, who has deliberately faced his greatest terrors to become stronger.
This journey has neutralized a key tactic of Vecna. More importantly, Will now knows what Vecna himself fears, and this may grant a critical advantage in the series finale that awaits.