🔗 Share this article The Mystery Within the Briefcase Henry Opens in Stranger Things? During the bulk of the concluding season of the popular Netflix show, Holly Wheeler and Max are imprisoned inside a mental fortress constructed from the recollections of the villain Henry. Their mission for freedom in episode 6 leads them to experience a defining event from Henry's childhood—a moment that potentially carries the means to overcome him once and for all. Heads Up: This article contains major spoilers for the concluding episodes. The Discovery in the Cavern When she finds Max in the mental landscape dubbed Camazotz, it becomes clear she is taking refuge in a grotto that Henry is terrified of. A clever observation a spyglass pilfered from Henry's old home helps Holly understand that the source of fear lies not within the cave. Matching her view through the cap, she and Max plummet into a subterranean passage. In this place, they observe a young, eight-year-old Henry encounter an man who is hurt and scared. As the boy offers aid, the man reacts violently, hitting him in the hand. Fighting for his life, Henry strikes the man down with a rock. "Is this what corrupted him?" Holly asks tearfully. It was a factor, but the trauma went deeper than a simple act of survival. Like many elements of the final season, the truth about the events in the tunnel was first explored the stage play Stranger Things: The First Shadow. A Naval Mystery and Stolen Research *The First Shadow* opens with the legendary naval test, which transported a vessel into a realm later called the Abyss. The ship was attacked, and the lone returnee was the captain, who emerged in a vegetative state with an different blood composition. The captain's son, Martin Brenner, attempted to recreate this phenomenon in the Nevada desert. But a disloyal lab worker pilfered lab samples to hand over to the Communist spies, who were eager to begin their parallel research. That traitor in the tunnel is the one who stole the materials. Unlocking the Mystery Given what is revealed about the doctor's experiments, the case almost certainly contained some of Captain Brenner's infected blood. In the scene, Henry is bleeding from his hand. Exposure likely occurred upon handling the contents, which triggered the origin of his telekinetic gifts—powers he would genetically impart to the children under Brenner's care. A second theory, the case could have held dark matter that was destined to travel to the Hawkins lab, where it acts to anchor the Upside Down. *The First Shadow* reveals that the boy was transported in the Abyss, reappearing 12 hours later with a new blood type and personality. Throughout the play, he struggles with the control of a malevolent force, much like how the character Will was influenced by the Mind Flayer in an earlier season. The Power of Fear Henry's enduring terror of that cave highlights how utterly horrifying the event was for him. Even as he commands the army of monsters and works to collapse the Abyss into Hawkins, a part of him remains. The villain weaponizes terror, and the narrative points to a climactic battle between Vecna and Will, who has confronted his own deepest fears to fortify himself. His confrontation has effectively disarmed Vecna. Furthermore, Will now knows what the monster's own weakness, potentially giving him a decisive edge in the endgame conflict to come.