What's Inside the Briefcase Henry Unlocks in the Hit Series?
During the bulk of the fifth and final season of the popular Netflix show, the young Holly Wheeler and Max are held captive inside a mental fortress forged from the memories of the villain Henry. The search for freedom in the pivotal sixth episode has them experience a traumatic incident from Henry's youth—a moment that potentially carries the means to overcome him permanently.
Spoiler Warning: This article details significant events for the concluding episodes.
The Discovery in the Mine Shaft
Upon meeting Max in the world dubbed Camazotz, Holly discovers she is hiding out in a chamber that Henry avoids at all costs. By leaving the lens cap on a viewing device found in Henry's old home helps Holly understand that the danger lies beyond the cave. By aligning her view to the cut-out, she and Max suddenly fall into a subterranean passage.
They watch a Henry as a boy come across an man who is hurt and scared. As the boy offers aid, the man panics and shoots, wounding the boy in the hand. Fighting for his life, Henry ends the threat with a rock. "Did this make Henry evil?" Holly questions through tears. It was a factor, but the trauma wasn't just a defensive killing.
Similar to other plot points this season, the truth about the encounter was first explored the theatrical production Stranger Things: The First Shadow.
The Philadelphia Experiment and Stolen Research
The play reveals the legendary naval test, which allegedly sent a vessel into a dimension later called the Abyss. Demogorgons assaulted it, and the sole survivor was the captain, who came back in a catatonic condition with an different blood composition.
This man's son, a young Martin Brenner, sought to replicate this dimensional breach in the Nevada desert. But a disloyal lab worker stole research materials to give to the Communist spies, who were eager to begin their version of the tests. That traitor in the tunnel was that very thief.
The Briefcase's Contents
Considering what is understood of the doctor's experiments, the case almost certainly contained some of Captain Brenner's infected blood. As shown, Henry is already bleeding. Exposure likely occurred upon handling the contents, leading to the origin of his telekinetic gifts—traits he would genetically impart to the children under Brenner's care.
A second theory, the case could have held exotic matter that eventually found its way to Hawkins Laboratory, where it maintains the stability of the Upside Down. *The First Shadow* reveals that Henry was transported in the Abyss, returning after half a day fundamentally changed. Throughout the play, he struggles with the whispers of a malevolent force, similar to how Will was possessed by the shadow monster in season 2.
A Weaponized Emotion
The reason Henry avoids the cave of that cave shows how deeply scarring the incident was for him. While he commands the collective consciousness and works to collapse the Abyss into Hawkins, a piece of the scared boy lingers. Fear is his tool, and the show is setting up a climactic battle between the monster and Will, who has deliberately faced his own deepest fears to become stronger.
Will's growth has effectively disarmed Vecna. Furthermore, Will now is aware of what Vecna himself fears, and this may grant a critical advantage in the endgame conflict to come.
