The Contents of the Briefcase Henry Opens in the Hit Series?

During the bulk of season 5 of *Stranger Things*, Holly Wheeler and Max find themselves trapped inside a mental fortress forged from the memories of Vecna. The search for freedom in episode 6 forces them to witness again a traumatic incident from Henry's youth—a discovery that could contain the secret to his downfall once and for all.

Editor's Note: This article details significant events for *Stranger Things* season 5, volume 2.

The Discovery in the Tunnel

Upon meeting Max in the world known as Camazotz, it becomes clear she is taking refuge in a grotto that Henry avoids at all costs. An accidental discovery a viewing device taken from Henry's old home allows Holly to realize that the danger lies outside of the cave. When she lines up her view to the cut-out, she and Max plummet into a subterranean passage.

They watch a young, eight-year-old Henry encounter an wounded, fearful individual. As the boy offers aid, the man fires a gun, striking Henry in the hand. Fighting for his life, Henry ends the threat with a rock. "Is this what corrupted him?" Holly asks tearfully. It was a factor, but the act wasn't just a simple act of survival.

Like many elements in volume 2, the truth about the encounter is detailed in the stage play Stranger Things: The First Shadow.

The Philadelphia Experiment and A Spy's Mission

This backstory explains the infamous Philadelphia Experiment, which transported a warship into a dimension known as the Abyss. Demogorgons assaulted it, and the sole survivor was the captain, who returned in a vegetative state with an altered blood type.

The captain's son, the future Dr. Brenner, sought to replicate this dimensional breach in remote Nevada. However, a treacherous employee took experimental components to give to the Soviets, who were eager to begin their version of the tests. That traitor in the tunnel was that very thief.

Unlocking the Mystery

Based on what is known about his research, the container most likely held samples of the unique blood type. At that moment, Henry is bleeding from his hand. He likely becomes contaminated upon contact with the blood, leading to the origin of his telekinetic gifts—traits he would inadvertently transfer to the children under Brenner's care.

A second theory, the case could have held dark matter that later made its way to Hawkins Laboratory, where it maintains the stability of the parallel world. The stage play explains that young Henry ended up in the Abyss, reappearing 12 hours later fundamentally changed. Throughout the play, he struggles with the whispers of a sinister presence, much like how Will Byers was possessed by the entity in an earlier season.

The Power of Fear

His lasting fear of that cave demonstrates how profoundly traumatic 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 lingers. Vecna uses fear, and the show is setting up a climactic battle between the monster and Will, who has overcome his personal demons to become stronger.

Will's growth has effectively disarmed Vecna. Crucially, Will now knows what the monster's own weakness, which could provide a key upper hand in the ultimate battle to come.