What's Inside that Briefcase Henry Unlocks in the Hit Series?
Throughout a large portion of season 5 of the popular Netflix show, Holly Wheeler and Max Mayfield find themselves trapped inside a mental fortress forged from the past of the villain Henry. Their quest for an escape route in "Escape from Camazotz" has them relive a defining event from Henry's youth—an event that may just hold the secret to his downfall permanently.
Editor's Note: The following contains major spoilers for *Stranger Things* season 5, volume 2.
The Discovery in the Cavern
When she finds Max in the mental landscape called Camazotz, it becomes clear she is taking refuge in a chamber that Henry is terrified of. An accidental discovery a telescope found in Henry's old home helps Holly understand that the danger lies beyond the cave. Matching her view through the cap, she and Max tumble into a deep mine shaft.
In this place, they observe a Henry as a boy find an injured and paranoid man. When Henry tries to help, the man fires a gun, striking Henry in the hand. In a desperate act of self-defense, Henry ends the threat with a rock. "Was this the turning point?" Holly questions through tears. Essentially, yes, but the act wasn't just a fight for life.
Like many elements in volume 2, the full story behind the events in the tunnel was first explored the stage play Stranger Things: The First Shadow.
A Naval Mystery and Stolen Research
This backstory explains the 1943 event, which allegedly sent a vessel into a dimension later called the Abyss. The ship was attacked, and the sole survivor was the ship's commander, who emerged in a catatonic condition with an different blood composition.
That survivor's offspring, the future Dr. Brenner, attempted to recreate this dimensional breach in Nevada. One of his scientists stole research materials to give to the Russian agents, who were eager to begin their version of the tests. The man in the tunnel is that employee.
Unlocking the Mystery
Considering what is known about Brenner's work, the container almost certainly contained samples of the altered blood. At that moment, Henry is already bleeding. He likely becomes contaminated upon contact with the blood, which triggered the awakening of his powers—traits he would later pass on to the children Brenner would experiment on.
A second theory, the box could have held dark matter that eventually found its way to Hawkins Laboratory, where it maintains the stability of the mirror dimension. The stage play explains that young Henry was transported in the Abyss, coming back after half a day with a new blood type and personality. Throughout the play, he struggles with the control of a sinister presence, similar to how Will was controlled by the shadow monster in the past.
A Weaponized Emotion
The reason Henry avoids the cave linked to that memory highlights how profoundly traumatic the event was for him. While he orchestrates the army of monsters and attempts to pull the Abyss into Hawkins, a fragment of his psyche still exists. The villain weaponizes terror, and the show is setting up a final confrontation between the monster and Will, who has deliberately faced his own deepest fears to become stronger.
His confrontation has neutralized a key tactic of Vecna. Crucially, Will now is aware of what Vecna himself fears, which could provide a key upper hand in the endgame conflict ahead.
