How the jaw-dropping one-shot episode in The Haunting of Hill House was almost a complete disaster

Well, sort of. Although it looks seamless, the episode – which takes place simultaneously in a funeral home and the titular house – is actually sewn together through a series of long shots and camera trickery. But it still required some 20-minute takes, a scarily huge task that almost got the better of the show.

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With stage actors often performing to audiences for lengthy periods of time, you might think a 20-minute take would feel routine to the cast, but the episode posed problems you simply wouldn't find in a theatre.

“I started memorising that episode two months before, as if we were doing a play. But we didn’t have the same rehearsal time,” says Elizabeth Reaser, who plays mortician Shirley Crain in the drama. “Normally in a play you get six weeks or longer to rehearse. We got two.”

It wasn’t just the cast that had to rehearse in such a short amount of time, but the crew too. Because not only did a heavy camera have to work its way around the set, but props were in constant movement behind the lens, with lights being changed on the go too.

“All of the behind the scenes things about [episode six] made it so exciting,” said Kate Siegel, who plays Theodora, adding navigating around the camera crew and equipment was like "being in a heard of elephants".

To make things even harder, all this behind-the-camera action limited the attempts the actors could manage in the two-day shoot.

“When you're doing an 18-minute take there's so many things that need to be reset,” explains Steven Crain actor Michiel Huisman (who you’ll probably know as Daario Naharis from Game of Thrones). “And it's not like you can do another right away. That's a 45-minute reset.

“And at the end, you're not going to have anything to cut away. There’s not going to be a close up to cover a little mistake.”

As it turned out, the cast and crew only got three attempts filming the episode, all thanks to a faulty camera dolly wheel. “The cart that moved the camera around had a specific sort of wheel to be used on hardwood floors only. But because of the carpet we had on set, the mechanism inside the dolly got messed up. The fibre of the carpet was getting wound up in the wheel after weeks of rehearsals,” explained Henry Thomas, who plays Hugh Crain.

By the third attempt, the camera cart was set to break. And that was a problem because they had only completed one take successfully, but, as Reaser said, the actors weren’t quite “popping” in it.

“Mike [Flanagan, director] was thinking 'we've got one take that's usable. I think we have to go for a second'. This is the take that ended up in the show. And this is not a joke: immediately on the completion of that take the cart broke. It did not move one more inch,” recalls Siegel.

And if the wheels would have failed a moment sooner? “They'd be no way we could have completed the episode,” said Thomas. Turns out the cart in question was a very expensive, very specialised piece of equipment that couldn’t have been replaced in time for a re-shoot.

Fortunately, the cast and crew didn’t need another attempt. The actors perfectly portrayed the tension and tenderness of a family reunion in a horrible circumstance, the camera and lightning capturing the episode's every twist and scare.

Technically, it’s a jaw-dropping piece of filmmaking. But, most importantly, it’s absolutely terrifying too.

The Haunting of Hill House is now available to watch on Netflix

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