What's Inside the Briefcase Henry Unlocks in Stranger Things?
For much of the fifth and final season of *Stranger Things*, Holly Wheeler and Max are imprisoned inside a mental fortress constructed from the recollections of Vecna. Their mission for freedom in "Escape from Camazotz" forces them to experience a life-altering moment from Henry's childhood—a discovery that could contain the means to overcome him once and for all.
Heads Up: This discussion contains major spoilers for *Stranger Things* season 5, volume 2.
A Journey Into the Mine Shaft
After locating Max in the psychic realm known as Camazotz, Max reveals she is sheltering in a grotto that Henry is terrified of. An accidental discovery a viewing device pilfered from Henry's old home allows Holly to realize that the true terror lies outside of the cave. When she lines up her view to the cut-out, she and Max tumble into a subterranean passage.
They watch a child version of Henry find an injured and paranoid man. As the boy offers aid, the man fires a gun, striking Henry in the hand. To protect himself, Henry strikes the man down with a rock. "Was this the turning point?" Holly wonders aloud. The answer is affirmative, but the event involved more than a defensive killing.
In keeping with mysteries in volume 2, the full story behind the mine shaft incident is detailed in the theatrical production The First Shadow.
The Philadelphia Experiment and Secret Science
*The First Shadow* opens with the legendary naval test, which allegedly sent a warship into a plane known as the Abyss. Demogorgons assaulted it, and the lone returnee was the ship's commander, who came back in a vegetative state with an entirely new blood.
That survivor's offspring, Martin Brenner, sought to replicate this experiment in Nevada. But a disloyal lab worker took experimental components to sell to the Soviets, who were eager to begin their version of the tests. The man in the mine shaft was that very thief.
The Briefcase's Contents
Based on what is known about Brenner's work, the briefcase would assuredly have samples of Captain Brenner's infected blood. As shown, Henry is bleeding from his hand. It's probable he was infected upon contact with the blood, causing the origin of his telekinetic gifts—traits he would later pass on to the kids under Brenner's care.
Alternatively, the container could have held exotic matter that later made its way to Hawkins Laboratory, where it maintains the stability of the mirror dimension. *The First Shadow* reveals that Henry was transported in the Abyss, coming back after half a day fundamentally changed. Throughout the play, he fights the control of a malevolent force, similar to how the character Will was influenced by the entity in an earlier season.
The Power of Fear
His lasting fear linked to that memory demonstrates how deeply scarring the encounter was for him. Even as he controls the Hive Mind and seeks to merge the Abyss into Hawkins, a fragment of his psyche remains. The villain weaponizes terror, and the show is setting up a showdown between the monster and Will, who has overcome his greatest terrors to become stronger.
Will's growth has effectively disarmed Vecna. Furthermore, Will now knows what the monster's own weakness, which could provide a key upper hand in the endgame conflict that awaits.
