At times, 'Knock at the Cabin' made the book's author want to 'run out of the theater'

Warning: This article contains spoilers for Paul Tremblay's award-winning 2018 horror novel "The Cabin at the End of the World" and its big-screen adaptation, "Knock at the Cabin."

In director M. Night Shyamalan's latest twisty thriller, "Knock at the Cabin," as in the apocalyptic novel on which it's based, Paul Tremblay's "The Cabin at the End of the World," a family vacationing in the countryside is visited by four armed strangers who offer them a terrible choice.

Led by the gentle and imposing Leonard (Dave Bautista), the assailants tell 7-year-old Wen (Kristen Cui) and her doting dads, Andrew (Ben Aldridge) and Eric (Jonathan Groff), that prophetic visions have shown them that the world will soon end, and that only their family can save it — by killing one of their own.

For much of the film, the screenplay, by Shyamalan, Steve Desmond and Michael Sherman, hews faithfully to the tense beats and details of Tremblay's novel ... until it doesn't. The film diverges from the novel's conclusion and, perhaps, what meaning viewers will take from the story. They're changes the author himself admits he's still processing, days after watching the film for the first time at its New York City premiere.

"There were times where I was tearing up at random things just because, wow, it was right out of the book — and other times I felt like I wanted to run out of the theater," Tremblay said with a laugh on Sunday, chatting from his home outside Boston. "But overall, I do like the movie."

Some changes from book to film are relatively minor, such as the order and manner in which some of the home invaders perish, compelled by an unseen power to die in ritualistic violence mostly kept offscreen (a stark contrast to the gory details that lend the book more intense brutality and dread).

A more significant change involves information that both the characters and audience are given. While the novel never says if Leonard, Adriane, Sabrina and Redmond's visions are real — or if the news reports they point to as evidence of the apocalypse are concrete proof, rather than coincidence — the movie makes it explicit, vindicating the strangers' actions.

Arguably the biggest difference is the fate of the young girl, Wen. In the movie, it's for her future that her fathers make the ultimate sacrifice as Eric — who becomes increasingly open to the possibility that the strangers' visions are true — makes peace with the gamble and convinces Andrew to kill him. Andrew is later shown with a grown Wen, their family having averted disaster in the nick of time.

Tremblay's book travels a more complex path: Wen is accidentally killed when Andrew and Leonard struggle over a gun, leaving her dads to make their decision in the throes of unimaginable grief. Left alone to decide humanity's fate, they reject the choice itself, defying any god that would put them through hell, enduring hate and homophobia to find their way to happiness, only to take their daughter and still demand more.

"I think the movie’s ending is way darker than my book," said Tremblay. Below, the author mulls over the film's ending and other changes from the book; the novel's five-year journey from page to screen; the advice he received from Stephen King on how to handle seeing his work adapted; and the tip he'd give to other writers dipping their toes into Hollywood: "Get an entertainment lawyer."

You started writing the book in 2016. What were you trying to explore with it then, and how has its meaning evolved for you over the years?

I wanted the book to try to mirror the anxieties and fears so many of us were feeling ... that helped inform the ending. Because I know some people don't think my ending is very hopeful, but I find my ending defiantly hopeful. Even more so now that the years have passed. When I wrote it, I tried to divorce myself from thinking about if there was an apocalypse or not. I purposely tried to keep each piece of information balanced. And at a certain point in telling the story it didn't matter to me if the apocalypse was happening because the story to me became, "What were Eric and Andrew going to choose?"

That was the story: their choice. Their ultimate rejection of fear and cruelty, whether or not the apocalypse is happening. What has happened in the cabin and what they're presented with is wrong; it's immoral, and they refuse. And I find that hopeful, especially in the context of when I wrote the book. Now that we're well beyond Trump's presidency — hopefully — and everything that's happened in 2020 and since, I believe if I read the book now, I don't think there's an apocalypse happening. But that's just my opinion.

The uncomfortable feelings we're being asked to wrestle with are in part the beauty of the book, aren't they?

I definitely underestimated the amount of people who would be angry about the ending, in terms of I never told them there was an apocalypse. It was never a consideration. I was frankly gobsmacked so many people were upset I didn't tell them. Going near religion for me, blundering into it a little bit because the book really wears my beliefs and fears on a sleeve … it represented my fears of, "What if there is a supreme being and it's terrible and cruel?" That probably touches a nerve with people one way or the other.

Why was it important that the family at the center of this story being asked to make this terrible choice are a gay couple? And how does that impact how the story, which ends differently in the film, might be interpreted?

I wandered blindly into the family a little bit at the beginning because I felt like it was going to be personal and a big deal, because it was going to be the seventh novel that I'd ever written. And aside from my wife, Lisa, who used to read all my stories, the first readers I really trusted were [my cousin] Michael and his husband, Rob, and my Aunt Mary, who is like a second mom to me, and her wife, Debbie. I've known those people and loved those people for almost as long as I can remember. I wanted to try to honor them and honor their experience somehow, with Andrew and Eric. So much of their experiences inform what I wrote.

I think the movie's ending is way darker than my book. I don't mean to say this flippantly. But politics aside, on a character level, the idea of, "What are Andrew and Wen going to do now?" Not only did they just kill Eric — how will they go on after with that knowledge? — but also with the knowledge that this supreme being that controls the universe was so unremittingly cruel to them? I would never write a sequel to "The Cabin at the End of the World," but I'm actually weirdly interested in a story of what Wen and Andrew do now.

Your novel maintains ambiguity around information such as whether or not the apocalypse is happening. The film makes it explicit that it is. How do you feel that changes the meaning of the story?

I knew in the first attempt to get it made ... financier after financier rejected it because no one wanted to see Wen die onscreen. Wen is really the fulcrum to me, in my imagination and in the difference between the two. Although I should say there are two things: Wen, and it not being ambiguous, changes everything.

As a parent, and without the larger political stuff happening with the queer dads, you can sort of understand, if the apocalypse is really happening and you want your child to continue to live, then maybe you can deal with that choice. I don't want to speak for Night, but I know he was really interested in the choice part. I'm agnostic ... he's coming at it from obviously a different cultural experience than I've had, but also a different religious experience. So I am still wrestling with the two different endings.

How much of the adaptation process were you privy to along the way, and what was that like to navigate?

I signed the option absurdly early, six months before the book even came out. Not that I'm that known now, but I was much more of a relatively unknown commodity. Why would anybody give me a say in what was going on? I had no contractual say. [Executives] Ashley Fox and Brad Zimmerman are no longer at FilmNation, but when they were there, they were great about letting me know what was happening. Eventually they let me read the second draft of the screenplay, and they asked for my notes, which I gave. I gave a lot of notes.

Was that early script very different from your novel?

Yes, the first screenplay was quite different. It was funny. There are things that can be the same. But I think it can be a hard story to tell if you change something that might seem minor [and] by the end, because it gets so ramped up and magnified, it's totally different. I felt like Night put a lot more of the book back in, especially in the early part of the movie, which was cool.

So they asked my opinion, but they didn’t have to listen to it. Once Night was interested in being the producer and eventually the director, I didn't see the screenplay until after filming. But I was very grateful that he called me in November of 2021. He said, "Hey, I love the book," and [shared] in broad strokes the changes that he was planning. I appreciate that he was upfront about that. From there, I would get questions about minor details that were fun to answer, like a random text — “Hey, where'd you get the ideas for the weapons? What'd you use for your design inspiration? What's this character's last name?”

Do you feel like you've fully processed the movie after seeing it twice?

I'm trying to. I've been thinking about it and answering more questions about it. Like I said, I like the movie. I prefer my ending. I hope that would be the case! Even though I had read the screenplay, it's just so different seeing it onscreen. It was a lot to take in. A fun experience, obviously, but still very, very strange.

I hadn't really considered how different [Eric] was [in the adaptation], because at a certain point, I'm so focused on Andrew in the movie. I'm Team Andrew: “Let's not do this!” But in the book, in everything you write, there's part of you. In a lot of ways, with the religious stuff, Eric represents 7-year-old me; my family was Catholic, briefly. I only made it to first confession when I was in second grade, and then we stopped going to church. But there is that Eric part of me, whereas the rational Andrew, I think, is the predominant part of me.

Your story is much gorier than the movie, as it places us in the room with these people and the violence they are experiencing and witnessing. How did you consider how far to take it?

I try to be considerate when I'm writing violence on the page. That's always a sticky question, if violence is entertainment, because “Evil Dead II” is one of my favorite movies of all time. But that's much different than the violence in “The Cabin at the End of the World.” I try to ask, if this were to happen in real life, what would it feel like? I wanted to try to treat the violence with dignity, or dignify the experience. What I mean by that is if anyone has ever had the misfortune of being assaulted or witnessing a violent act, whether you are the victim or one of the witnesses [or] even the perpetrator, you're going to be fundamentally changed by that event. My hope is that that's what is represented in the book.

At the same time, it is so brutal because I want to remind the reader that this is what is being asked of the family. They're being asked to do what you're seeing them act out. I wanted, even just subconsciously, to make it harder for the reader to envision the family choosing to do this — to participate in this brutal, awful violence.

What advice did Stephen King give you on having your novel adapted?

He tweeted about my first horror novel, “Head Full of Ghosts,” and that honestly gave me my career. When he tweeted about it on Aug. 19, 2015 — yes, I have that date memorized — the tweet went like wildfire and gave the book a second, third, fourth wave. He's been an amazingly gracious supporter of my work. He read "Cabin" early, before it came out in July 2018. Maybe a month after, there was an earthquake in the Aleutian Islands and there was a tsunami warning. Thankfully there were no tsunamis on the mainland. Everything was fine. Then I got a little email from Stephen King that said "Earthquake, Aleutian Islands — quick, sacrifice somebody!”

I emailed him when I was dealing with the new world of producers and the studio's wants, asking, "What was it like seeing some of your adaptations?" And he said, "Sometimes it felt like I was walking into the story in my own head." That certainly wasn't the case for me because I imagined something totally different for the characters and the setting. But it was still unmooring to walk into this cabin and see Dave Bautista and Ben [Aldridge] and Jonathan [Groff] tied to a chair, and there's Wen [played by Kristen Cui]! That was nice. It wasn't what I imagined, but it looks great and I think the actors certainly inhabited the emotional lives of these characters.

Some fans took issue with your name not being included in the marketing of this movie, and that it was not more clearly advertised as being adapted from your book. Was that a contractual issue? And with some of your other novels optioned for the screen, would you handle that part of the process differently in the future?

There was contractual stuff, and Universal and my side of the street had a slight different interpretation in one line of their contract about if the screenwriters get credit, where the author gets credit. As an old lefty, I love that the WGA is so powerful. I wish novelists had a union that strong. But certainly no one out there needs to feel bad for me. It's all a learning experience, and I'm very happy that now the movie is out. And the night of the premiere, [Shyamalan] gave a speech before the movie, and he talked quite a bit about the book and was very emotional.

As Stephen King gave you advice, what advice would you pass on to other authors having their novels adapted?

Again — not my experience — but going through this I heard from so many other writers who have been adapted sharing tales of not being treated well. I'm not putting myself in that category. But because I was going through it, I would hear from other people. So my biggest advice would be: Get an entertainment lawyer to help you with contracts.

I have agents, but entertainment lawyers are going to be a little bit more in-depth at manipulating what you want into the contract. But it's a hard decision to make because, again, without a union, you're left afloat — it's another 5% that you have to give up on top of the 15% for your agent. If you had a manager, that's another 10%. All that stuff is dizzying. So many of us writers, me included, aren't lawyers. I studied math! I don't know how I became a writer. But I certainly didn't study contracts.

This story originally appeared in Los Angeles Times.