The Contents of that Briefcase Henry Opens in the Hit Series?
During the bulk of the fifth and final season of *Stranger Things*, Holly Wheeler and Max are imprisoned within a psychic prison constructed from the recollections of Vecna. Their quest for freedom in episode 6 forces them to relive a life-altering moment from Henry's childhood—a discovery that could contain the means to overcome him for good.
Spoiler Warning: The following reveals crucial plot points for *Stranger Things* season 5, volume 2.
The Discovery in the Mine Shaft
Upon meeting Max in the psychic realm dubbed Camazotz, Max reveals she is sheltering in a cave that Henry strangely fears. A clever observation a telescope found in Henry's old home allows Holly to realize that the danger lies not within the cave. Matching her view to the cut-out, she and Max tumble into a subterranean passage.
In this place, they observe a child version of Henry find an wounded, fearful individual. Attempting assistance, the man reacts violently, striking Henry in the hand. In a desperate act of self-defense, Henry kills the man with a rock. "Is this what corrupted him?" Holly wonders aloud. It was a factor, but the event wasn't just a defensive killing.
Similar to other plot points in volume 2, the significance of the events in the tunnel was first explored the theatrical production The First Shadow.
A Naval Mystery and Secret Science
*The First Shadow* opens with the infamous Philadelphia Experiment, which transported a U.S. Navy ship into a dimension later called the Abyss. The ship was attacked, and the sole survivor was the captain, who emerged in a vegetative state with an different blood composition.
The captain's son, the future Dr. Brenner, sought to replicate this dimensional breach in remote Nevada. One of his scientists pilfered lab samples to hand over to the Communist spies, who were keen to start their own interdimensional projects. The man in the tunnel is that employee.
Unlocking the Mystery
Considering what is understood of his research, the briefcase most likely held some of the altered blood. At that moment, Henry is bleeding from his hand. It's probable he was infected upon contact with the blood, leading to the development of his psychic abilities—powers he would inadvertently transfer to the test subjects Brenner would experiment on.
Alternatively, the case could have held dark matter that was destined to travel to the secret facility, where it helps stabilize the Upside Down. The prequel shows that young Henry somehow wound up in the Abyss, coming back 12 hours later with a new blood type and personality. From then on, he struggles with the influence of a sinister presence, reminiscent of how Will was influenced by the Mind Flayer in an earlier season.
A Weaponized Emotion
Henry's enduring terror associated with the mine demonstrates how deeply scarring the event was for him. Even as he orchestrates the collective consciousness and works to collapse the Abyss into Hawkins, a piece of the scared boy remains. Vecna uses fear, and the show is setting up a showdown between the monster and Will, who has overcome his greatest terrors to fortify himself.
Will's growth has effectively disarmed Vecna. Furthermore, Will now understands what Vecna himself fears, which could provide a critical advantage in the series finale ahead.
