The First Shadow’ And How The Play Connects To Season 5

Spoilers ahead, so proceed with caution if you haven’t watched Volume 1 yet.

It’s been a few days since Volume 1 of Stranger Things dropped, and fans are heading into Volume 2 (out Christmas Day) with plenty of questions. One of the biggest mysteries viewers are trying to unravel is how Henry’s past, also known as Vecna and now Mr. Whatsit, ties into the cave and his deepest fears in Season 5.

Mr. Whatsit is introduced in Season 5 as an imaginary figure Holly talks to throughout the first few episodes. She sees him at home and at school, and his name stems from her favorite book, A Wrinkle in Time. According to Holly, Mr. Whatsit warns her about the monsters in Hawkins and wants to protect her.

After Holly and the Wheelers are attacked, she’s kidnapped by a Demogorgon and taken into the Upside Down. Later, her mother, Karen, reveals that Mr. Whatsit went by another name: Henry Creel, the series’s primary antagonist, better known as Vecna. For context, Henry was the first test subject of Dr. Martin Brenner at Hawkins Lab and possesses powerful telekinetic and telepathic abilities similar to Eleven’s.

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Eleven banished Henry to the Upside Down, ultimately transforming him into Vecna, the monster who hunts and kills victims by invading their minds. In Season 5, he fixates on the children of Hawkins, abducting 12 of them, and admits in Episode 4 that he plans to reshape the world with their help.

Vecna calls the children the “perfect vessels” for his master plan to reshape the world to his liking. “Do you know why I chose them to reshape the world?” he asks Will Byers, who is also connected to Vecna and the hive mind. “It’s because they are weak. Weak in body and mind.” He then tells Will that he was the one who showed him what was possible.

While Hawkins is under attack by Demogorgons, Holly becomes trapped inside Henry’s memories. Vecna continues to appear to her as the gentle Mr. Whatsit, keeping Holly under the impression that she’s safe and he’s trying to help. He brings her to his childhood home and warns her not to leave the house or go into the woods, where the monsters are.

But Holly’s curiosity gets the best of her when she hears a mysterious knock on the door and finds a letter in the mail, apparently from Henry, urging her to venture into the woods to a specific spot to help him. When she arrives, she doesn’t find Henry. Instead, she sees Max, who has been trapped inside Henry and Vecna’s memories while her physical body remains in a coma at the hospital.

After exploring Henry’s memories, both the good and the ugly, Max takes refuge in a cave that Henry refuses to enter. Max tells Holly that she doesn’t know why Henry is afraid of the cave. However, the live prequel play, Stranger Things: The First Shadow, offers hints that could provide clues for viewers ahead of Volume 2.

How Does Henry’s Fear Of The Cave Connect To Stranger Things: The First Shadow?

In The First Shadow, Dr. Brenner reveals that Henry’s psychic abilities trace back to an incident in his childhood in the Nevada desert, when he wandered into a cave on his eighth birthday. The cave contained stolen government technology designed to replicate a World War II experiment that sent a battleship to another dimension.

While missing inside the cave, Henry was pulled into the other dimension and encountered the Mind Flayer for the first time, an experience that altered both his personality and his blood type. The incident left Henry permanently connected to Dimension X, and the trauma he endured in the cave is likely the reason he can no longer return to it.

Co-creator Matt Duffer confirmed to Variety that the cave in The First Shadow is the same one Max and Holly enter, and the same one Henry refuses to go inside.

“When we were working on the play with Kate Trefry, we had Henry’s backstory worked out. There was always a balance that we had to find in terms of how much we were going to put in the play,” he explained, adding that he insisted on saving certain plot details for the Netflix series.

“We were pushing back and saying, ‘Well, we have to wait to reveal that in the show.’ You’ll see, especially as you reach the final episode, there’s more overlap with the play,” he continued.

How To Watch Stranger Things: The First Shadow

Unfortunately, there are no official recordings of Stranger Things: The First Shadow. The only way to watch the Stranger Things live prequel play is to see it in person in London or New York.

In April 2025, Netflix released a documentary about the making of the play titled Behind the Curtain: Stranger Things The First Shadow, which is streaming on the platform.

The New York Broadway production of Stranger Things: The First Shadow, which opened in April 2025, is playing at the Marquis Theatre. You can purchase tickets here.

Meanwhile, the show in London’s West End is playing at The Phoenix Theatre. You can book tickets starting in December 2025 through May 2026.

Stranger Things Season 5, Volume 1 is streaming on Netflix. Check out the official trailer below.