🔗 Share this article What's Inside that Case Henry Unlocks in the Hit Series? Throughout a large portion of the concluding season of the popular Netflix show, the young Holly Wheeler and Max find themselves trapped in a realm of memories built from the past of Vecna. The search for an escape route in the pivotal sixth episode forces them to relive a defining event from Henry's childhood—an event that may just hold the secret to his downfall once and for all. Heads Up: This article reveals crucial plot points for the second part of the final season. Unearthing the Secrets of the Mine Shaft After locating Max in the psychic realm dubbed Camazotz, Holly discovers she is taking refuge in a cave that Henry is terrified of. A clever observation a viewing device taken from Henry's old home helps Holly understand that the true terror lies outside of the cave. Matching her view through the cap, she and Max suddenly fall into a subterranean passage. They watch a Henry as a boy come across an injured and paranoid man. Attempting assistance, the man reacts violently, striking Henry in the hand. To protect himself, Henry kills the man with a rock. "Was this the turning point?" Holly questions through tears. It was a factor, but the event involved more than a defensive killing. In keeping with mysteries in volume 2, the full story behind the events in the tunnel is detailed in the stage play Stranger Things: The First Shadow. An Interdimensional Incident and A Spy's Mission The play reveals the infamous Philadelphia Experiment, which reportedly teleported a vessel into a dimension known as the Abyss. Demogorgons assaulted it, and the only one to return was the captain, who came back in a unresponsive state with an entirely new blood. That survivor's offspring, the future Dr. Brenner, sought to replicate this dimensional breach in the Nevada desert. However, a treacherous employee pilfered lab samples to give to the Russian agents, who were keen to start their own interdimensional projects. This spy in the cavern is that employee. The Briefcase's Contents Considering what is understood of Brenner's work, the briefcase most likely held some of Captain Brenner's infected blood. As shown, Henry is bleeding from his hand. It's probable he was infected upon handling the contents, causing the awakening of his powers—abilities he would later pass on to the kids under Brenner's care. Another possibility, the box could have held strange particles that was destined to travel to the secret facility, where it maintains the stability of the Upside Down. The stage play explains that Henry ended up in the Abyss, returning after half a day with a new blood type and personality. From then on, he battles the influence of a malevolent force, similar to how Will was controlled by the Mind Flayer in an earlier season. A Weaponized Emotion His lasting fear associated with the mine shows how profoundly traumatic the incident was for him. While he commands the army of monsters and works to collapse the Abyss into Hawkins, a piece of the scared boy still exists. The villain weaponizes terror, and the show is setting up a climactic battle between the monster and Will, who has confronted his personal demons to gain strength. This journey has taken a weapon from Vecna. Crucially, Will now understands what the monster's own weakness, and this may grant a critical advantage in the ultimate battle that awaits.