Foe author and director talk twists, AI, and how they originally wanted the movie to be nothing like the novel

"I really wanted to not feel any strict loyalty or be beholden to the book," author Iain Reid says of the upcoming adaptation of his angsty sci-fi drama Foe. "It was its own thing; the concrete had been poured, the book is done. It's there on the side."

In the end, however, Foe – the movie – wound up following the novel which it's based on to the literal letter, lifting exact phrases and visuals from the page. To delve into the plot too much feels dangerous, given how the narrative partly hinges on a real rug-pull of a twist in the second half, too. But essentially, the flick follows a country-living couple, trying their best to sit out an impending environmental apocalypse, as their marriage becomes threatened by a stranger's unexpected visit – and his life-altering request.

While it may not be immediately clear to viewers, given the emphasis on screen time for Paul Mescal's Junior, director Garth Davis points out one of the only major differences to GamesRadar+, and that's that his take is told from the perspective of Saoirse Ronan's Hen, unlike the source material.

"I wanted Garth, especially Garth, to feel the freedom to really explore the themes of this relationship, to talk about how we could make it cinematic," says Reid. "My approach was to not feel precious about the book at all, but to use it and to really think about these ideas and and then start writing. I didn't want Garth to feel any pressure that there were certain parts he had to include. It was carte blanche, you know, from my point."

"There's so much of the book that I loved," Davis adds, gushing about how "unique" he found Reid's story. "I just thought it was such an unusual and exciting way to explore a relationship, the elements of AI, and our habitat in this classic mystery thriller way. It seemed like a great way to bring an audience into a very deep place and look at this relationship at its heart."

"I wasn't too concerned about trying to protect the twist or anything. That became really just a way to tell the story in a kind of interesting and fruitful way, to get at this relationship and get sort of a insight into the relationship," Reid chimes in. "But if there's aspects of the story that people pick up on early, that's great. If some people are surprised by the end by what they've been watching, or see it as a twist, that's great, too. It's up to each viewer, but certainly, I wasn't – and I felt this way in the book – I never felt too pulled into trying to hide anything. It didn't seem to me to be that kind of story."

Canadian author Reid is no stranger to having his works adapted for the screen. Before Foe, Charlie Kauffman reimagined his psychological thriller I'm Thinking of Ending Things into a Netflix film, starring David Thewlis, Toni Collette, Jesse Plemons, and Jessie Buckley – though he was only involved in the project as an executive producer. Due to the book's philosophical, surrealist tone (and the fact that it takes place almost entirely in a car), Reid never anticipated it'd be of interest to filmmakers, so it was a "huge surprise" when Kauffman came a-knocking. Reid admits he had a similar reaction when Davis started up a conversation with him about Foe; only this time around, he wanted to co-write the screenplay.

"[Charlie] was so nice to me, and allowed me to sort of see that whole process," he recalls. "With Garth, it was obvious early on that we had a similar vision. After I'm Thinking of Ending Things, I felt like I had a little bit of experience now and it would be interesting to try and actually write it with someone. I didn't go to film school and I wasn't someone who had read a ton of screenplays, and I sort of felt like that was a good place to be coming at it from. I wanted to just use instinct, collaborators to talk to, and I just wanted to try things. It was so fun to revisit the material with someone else who had new ideas and a fresh take on it, and to start discussions. I think that's sort of what the whole movie is, in my mind, it's hopefully it's a discussion starter. If people see it, maybe they'll want to talk about it..."

While Foe keeps audiences in the dark regarding the climate crisis Hen, Junior, and the rest of humanity seem to be facing, or the true nature of Terrance's (The Underground Railroad's Aaron Pierre) intentions at the start, the tension between the three characters – and the strain Terrance's arrival puts on Hen and Junior's already tempestuous romance – is bound to prompt dialogue. While, yes, there's an AI element to the tale that we won't go into here, it's evident that Reid and Davis's focus was on the merging of two minds and how two people who were right for one another once, may not always be. It asks tough questions, like, if your relationship had a shelf life, would it change anything? Much of the movie's action takes place in Hen and Junior's farmhouse, where true feelings are often left unsaid until emotions boil over. Davis insists, mind, that it was a light-hearted shoot.

"There was a lot of great camaraderie and great energy on set. But there was also just a lot of excitement," Davis, who previously helmed the likes of Lion and Top of the Lake, tells us. "I mean, in a weird way, actors just really love the challenge of something that's very simple. A lot of this is literally people talking in a room, but the material is so complex in that you think you're watching the story that's really happening, and all those secret glances and those secret relationships are like all these super rivers running through the scenes. All of that is just so ripe for an actor. It never felt intense, it felt exciting."

For Davis, "casting was critical" as he knew the movie would live or die on the performances of its main trio: "It's such a three hander". For Hen, he wanted someone who could embody the character's radicalism, as she fights for her own agency and fights for change in general. He was also looking for something who "emanated something precious". Ronan fit the bill and then some.

"Saoirse has that no matter what character she plays," he gushes. "She's got a gorgeous light that comes through her spirit. We cast her in the first week and then we found Paul, who was really desperate to do the job, and he had such a beautiful take on the material. I mean, it was just so obvious that I can't believe they've never worked together. They had such a respect and love for each other before they even got to work together. So that just felt really right, and that's the heart of the movie. So, we feel very good about that. Then Aaron Pierre? Such a beautiful actor and he brought fresh choices and such nuance to this layered antagonist."

"When I actually started to see the work [of Mescal, Pierre, and Ronan], I was astounded," says Reid. "It was so much better than I could have imagined. The performances are all singular; I can't imagine anybody else else doing it. Their work is just amazing. I love those guys for what they've done and I'm grateful."

When watching Foe, it's easy to be reminded of titles such as Annihilation, Ex Machina, or other Alex Garland works, or dread-soaked dramas like Never Let Me Go or perhaps, even, Ronan's 2013 outing How I Live Now. While Davis cites Hitchcock as a reference of his, as well as John Cassavetes, Reid reveals he had Jonathan Glazer's Under the Skin in his head all the time they were making the new movie.

"It's a novel I really loved as a reader," he explains. "I love the film adaptation, too. Something I really appreciate it, both the book and the film, is that they sort of exist somewhere between genres. Some people think it's science fiction. To me, it's not at all. It's just using elements of that to really get at a very moving story, something that's very rich and complex. Sometimes I'll see the novel in the science fiction section and I don't really understand that. To me, it just felt bold to take aspects of genres and really try and get at something." Foe, it's fair to say, attempts the same thing.

Foe releases in UK and Ireland on 20 October. For more, check out our list of the most exciting upcoming movies heading our way throughout the rest of 2023 and beyond.