What's Inside the Briefcase Henry Opens in the Hit Series?
For much of the concluding season of the popular Netflix show, Holly Wheeler and Max find themselves trapped inside a mental fortress constructed from the past of Henry Creel. Their mission for a way out in the pivotal sixth episode forces them to relive a traumatic incident from Henry's early years—a discovery that could contain the secret to his downfall for good.
Spoiler Warning: The following contains major spoilers for the concluding episodes.
The Discovery in the Mine Shaft
After locating Max in the psychic realm dubbed Camazotz, Max reveals she is sheltering in a grotto that Henry avoids at all costs. By leaving the lens cap on a viewing device taken from Henry's old home allows Holly to realize that the source of fear lies beyond the cave. When she lines up her view to the cut-out, she and Max tumble into a subterranean passage.
They watch a young, eight-year-old Henry encounter an man who is hurt and scared. When Henry tries to help, the man reacts violently, hitting him in the hand. Fighting for his life, Henry ends the threat with a rock. "Did this make Henry evil?" Holly questions through tears. The answer is affirmative, but the event involved more than a simple act of survival.
Like many elements this season, the truth about the encounter is detailed in the theatrical production The First Shadow.
A Naval Mystery and A Spy's Mission
This backstory explains the legendary naval test, which transported a warship into a realm dubbed the Abyss. The ship was attacked, and the only one to return was the ship's commander, who came back in a catatonic condition with an altered blood type.
That survivor's offspring, a young Martin Brenner, wanted to repeat this dimensional breach in the Nevada desert. But a disloyal lab worker stole research materials to sell to the Russian agents, who were eager to begin their own interdimensional projects. The man in the tunnel is that employee.
So, What's in the Case?
Given what is known about his research, the case would assuredly have vials of Captain Brenner's infected blood. As shown, Henry is already bleeding. He likely becomes contaminated upon contact with the blood, which triggered the origin of his telekinetic gifts—powers he would later pass on to the kids in Hawkins Lab.
Another possibility, the box could have held dark matter that eventually found its way to the secret facility, where it maintains the stability of the mirror dimension. The prequel shows that Henry was transported in the Abyss, returning after half a day fundamentally changed. As a youth, he struggles with the whispers of a malevolent force, reminiscent of how the character Will was influenced by the entity in season 2.
A Weaponized Emotion
The reason Henry avoids the cave associated with the mine shows how utterly horrifying the event was for him. Even as he controls the collective consciousness and works to collapse the Abyss into Hawkins, a part of him lingers. Vecna uses fear, and the narrative points to a climactic battle between the monster and Will, who has deliberately faced his greatest terrors to gain strength.
His confrontation has taken a weapon from Vecna. Crucially, Will now is aware of what Vecna himself fears, which could provide a decisive edge in the endgame conflict to come.
