You Should Have Left is the best kind of haunted house flick for the age of coronavirus

While there's no way horror magnate Jason Blum could have predicted that everyone watching Blumhouse Studios' latest offering — the modern haunted house horror You Should Have Left — would be trapped inside their own homes due to a pandemic, there's a sick kind of poetry to it.

"Ninety-five percent of the movie takes place inside the house," Blum told SYFY WIRE. "Definitely you'll feel better than the characters in the movie, almost no matter what because they are in a very bad way, so maybe, in that way, it's cathartic."

At least, that's the hope. You Should Have Left, written and directed by genre superstar screenwriter David Koepp, follows retired banker Theo Conroy (Kevin Bacon), his actress wife Susanna (Amanda Seyfried), and their young daughter Ella (Avery Tiiu Essex) to a rental house in the Welsh countryside where they hope to get away from the trials and tribulations of their shared life. But Theo is paranoid that Susanna is cheating on him, while Susanna struggles with Theo's potentially violent past and their age difference — the kinds of things you can't just bury behind a faux-happy-family veneer.

Soon enough, the house takes hold. This modern mansion, perched on an idyllic patch of emerald-green grass, may not look like the kind of haunted house audiences are used to — all creaking timbers and slamming doors — but the quiet, unexpected elements make it all the more disturbing; it's bigger on the inside, stairwells disappear behind minimalistic bookcases, and Theo keeps losing chunks of time.

"Obviously I love haunted house movies, I've done a ton of them, but I'm always trying to figure ones out that feel unusual or different... and this one was that," Blum says. "It was a haunted house movie, but a story in a haunted house I'd never seen."

You Should Have Left is loosely based on the novella of the same name by German author Daniel Kehlmann (while the initial story takes place in Germany, Koepp shifted it to Wales "because I wanted them to speak English"). The final product, though, is more of a mashup of Kehlmann's book and a script Koepp had been playing around with for some time, and which Bacon, whom he'd previously worked with on 1999's Stir of Echoes, had been circling.

"I had been really pounding the table to try to get him to make another movie with me and I was wearing him down and we started to talk about the idea of doing a horror movie that surrounded a marriage," Bacon, who also produced the film, told SYFY WIRE. "And I could see the wheels turning and he really started to construct this story and we had a lot of back and forth about it and we were pretty far along — he might have even written the outline. And then, strangely, I read the book when we already had our story and the book was shockingly close to the story that we had."

Bacon suggested to Koepp that they combine the two stories — Koepp's script and Kehlmann's novella — for the greatest effect. "While there's a lot of differences between the two, the essence of it is, I think, these two people in this strange house," Bacon explains.

"I had a very specific idea for the marriage from the beginning," Koepp explains. "We've seen Hollywood have a much older man and a younger woman many times and it's always covered up. We always kind of just are supposed to not notice that they are completely inappropriate couples. I wanted from the first scene to have us feel, ‘OK, this marriage is fatally flawed and this is why. They're not talking about it, but it's going to come up.' I wanted to see what that dynamic is like and what the suspicions were like, and what the tensions would be like in the marriage.

"But it's a fraught subject and I didn't want to offend people right out of the gate," he continues. "So I said, ‘Kevin, I'm going to make a lot of jokes about how old you are and I'm going to start right away and do it frequently.'"

Credit: Universal Pictures

Bacon had no problem with the jabs, and was all for holding his characters' behavior under a microscope, just as the house does in the film.

"As you get older, sometimes you are finding yourself reflecting on your past and you're starting to reflect on whether or not you've clouded your memories in some way or you're remembering things different from what actually happened," Bacon muses. "Especially when you see in this day and age now there's these kinds of digital footprints that are staying with us and you see people feeling regret and having to apologize for things that they've done in their past. And then it makes you kind of start to think about yourself in that context."

That's the kind of story Blum hopes viewers have come to expect from Blumhouse. You Should Have Left is the fourth feature-length Blumhouse production this year, and there's still plenty to come.

"I want there to be some edge," Blum says of the projects he's choosing at this point. "Either they make us scared or uncomfortable or nervous or they're provocative." That's what he refers to as "the Blumhouse DNA."

And because of the pandemic, the story turned out to be more provocative than anyone involved could have predicted. "I would say that everything that we react to now is through the lens of what's been happening the past few months," Bacon says.

"Being so isolated is nice for a point in time, just for a week, maybe, when you want to get away — which is what they [in the movie] wanted to do," Seyfried told SYFY WIRE. "But now this is the reality of everyday life. It's like you're stuck with who you're stuck with... or you're alone, and trying to negotiate your way through the world, trying to continue being isolated in a certain way. It's just weird timing for this movie to be coming out because it's very frustrating for very, very many people."

Seyfried goes on to say that she hopes quarantine helps with people's experience watching the movie but that, more than anything, she's just happy there's a new story out there now for people to experience. "We're all watching so much right now… there's so much content, but we're running out of it," she says. "I always want to see a new thriller, and I think people will get to be distracted for a couple of hours."