🔗 Share this article The Mystery Within the Briefcase Henry Opens in the Hit Series? For much of season 5 of the popular Netflix show, Holly Wheeler and Max are imprisoned in a realm of memories forged from the recollections of the villain Henry. The search for an escape route in episode 6 leads them to relive a life-altering moment from Henry's youth—a moment that potentially carries the key to defeating him once and for all. Spoiler Warning: This article details significant events for the second part of the final season. The Discovery in the Cavern When she finds Max in the mental landscape called Camazotz, Holly discovers she is taking refuge in a cave that Henry avoids at all costs. An accidental discovery a spyglass pilfered from Henry's old home allows Holly to realize that the danger lies outside of the cave. Matching her view with the shape, she and Max tumble into a abandoned tunnel. In this place, they observe a child version of Henry find an wounded, fearful individual. As the boy offers aid, the man panics and shoots, hitting him in the hand. Fighting for his life, Henry ends the threat with a rock. "Did this make Henry evil?" Holly asks tearfully. The answer is affirmative, but the trauma involved more than a defensive killing. Like many elements this season, the truth about the events in the tunnel is detailed in the live show the prequel play. A Naval Mystery and Secret Science This backstory explains the legendary naval test, which transported a U.S. Navy ship into a realm known as the Abyss. The ship was attacked, and the sole survivor was the captain, who returned in a vegetative state with an entirely new blood. The captain's son, the future Dr. Brenner, attempted to recreate this dimensional breach in remote Nevada. However, a treacherous employee took experimental components to give to the Russian agents, who were keen to start their parallel research. The man in the tunnel is that employee. Unlocking the Mystery Given what is understood of Brenner's work, the briefcase most likely held samples of the unique blood type. At that moment, Henry is bleeding from his hand. It's probable he was infected upon contact with the blood, leading to the awakening of his powers—powers he would inadvertently transfer to the children Brenner would experiment on. Another possibility, the box could have held exotic matter that was destined to travel to the Hawkins lab, where it acts to anchor the mirror dimension. *The First Shadow* reveals that the boy somehow wound up in the Abyss, reappearing hours later with a new blood type and personality. As a youth, he fights the whispers of a malevolent force, similar to how Will was possessed by the entity in an earlier season. A Weaponized Emotion His lasting fear of that cave highlights how utterly horrifying the incident was for him. Even as he controls the army of monsters and seeks to merge the Abyss into Hawkins, a fragment of his psyche remains. The villain weaponizes terror, and the series is building toward a climactic battle between Vecna and Will, who has confronted his own deepest fears to fortify himself. His confrontation has effectively disarmed Vecna. Furthermore, Will now knows what Vecna himself fears, which could provide a decisive edge in the endgame conflict ahead.