Netflix's 'The Haunting of Hill House' director explains how he kept the show's biggest mystery hidden

haunting of hill house

Warning: Spoilers for "The Haunting of Hill House."

Mike Flanagan, the director of Netflix's "The Haunting of Hill House," revealed how he kept the secret of the "Red Room" hidden from the audience.
He said that the set had to be "constantly refined."
He added that there needed to be one element that was constant so that it would feel familiar when revealed, and that was a "vertical window."
Flanagan also said that Hugh Crain could never open the room because "he exerts control over the house, on a physical level."

There are plenty of mysteries in Netflix's hit new horror series, "The Haunting of Hill House," but the biggest was hidden in plain sight the entire time.

That means that director Mike Flanagan had to go to great lengths to keep the secret of the "Red Room" hidden from the audience. Throughout the first season, the characters are unable to open a red door when living in the haunted Hill house as children. When they return to the house as adults, they finally discover that they had each actually been in the room countless times, and it acted as their own personal spaces that nobody else could unlock.

Flanagan told The Wrap that to conceal what the Red Room was from viewers, the set was "constantly refined."

"But we needed one element to be constant so that once the reveal occurred, a second viewing would feel like it was always obvious," Flanagan said. "We chose that distinct vertical window. We also made sure to shoot the room from the same angle in all of the episodes leading up to it, so that even the camera framing was familiar. We really just hoped that Hill House was so sprawling, people would assume there were just a lot of rooms they hadn’t seen. What’s odd if they look a little similar?"

Flanagan also explained why the room never opened for Hugh Crain, the father of the series, played by Henry Thomas in the past and Timothy Hutton in the present.

"Hugh is a man who fixes things," Flanagan said. "He exerts control over the house, on a physical level. He is in charge of the physical work being done to it, and that gives him a sense of security, comfort, and order. To put him in a position where he is incapable of something as simple as opening a door strikes to the very heart of his confidence as a character. Between that and the mold, I think it erodes his sense of competence, and everything else tumbles for him as a result."

But that doesn't mean that Flanagan didn't envision what the room would be like for Hugh, saying that it would have been "full of tools and other things from his work."

Join the conversation about this story »

NOW WATCH: How 'The Price Is Right' is made