For her marvelously unsettling feature directorial debut “Amulet,” Romola Garai had been looking for just the right place to put a nightmarish composition from her composer Sarah Angliss, a cascading cacophony of sirens singing that grows more warped as it wears on turning ecstasy into agony and back again. It had been intended for a scene set in a club from earlier in the film where the sonic descent into hell might have been a little much when ambient pop music made more sense, but even if she couldn’t know yet for certain that moviegoers would be stunned stiff at the end of “Amulet” as they were at the film’s premiere at Sundance, ensuring a captive audience, the idea of leaving audiences even more shaken from what they’d seen was appealing, and that was before someone else from the crew thought they could do one better.

“It was actually our graphic title designer who just said, ‘People don’t usually do this, but I have an idea…’” recalls Garai of the film’s closing credits that are as gloriously warped as the film that preceded it. “I just loved it straight away because the whole film is about flipping and reversing very obvious things.”

“Amulet” is about as far away from obvious as you can get, beginning with the surprising turn that in Garai’s illustrious career as an actress, she’s been in just one proper horror film (Ruiari Robinson’s “The Last Days on Mars”), but she proves to be a brilliant director of them with this twisted tale of a former soldier named Tomaz (Alec Secareanu) who has spent the last two years on the streets after once standing guard at a checkpoint in a foreign war and whose fortune could change upon meeting Magda (Carla Juri), after being brought together by a local nun (Imelda Staunton) who believes Tomasz could provide a handyman for the young woman who has devoted herself to taking care of her sickly mother in exchange for a roof over his head. The arrangement seems simple enough, particularly when Tomasz and Magda have experienced isolation and trauma in such a way that makes it easier to relate to each other after some initial awkwardness, but it doesn’t account for all the secrets that both have had to keep, nor the many that the house itself has.

Once a gatekeeper, Tomaz finds himself on the other side of the fence in “Amulet” in a variety of ways and Garai’s delirious rewrite of a ‘70s Hammer horror film reveals itself to be impressively progressive in terms of its gender politics, creating an atemporal space for Tomaz and Magda that speaks directly to the one we’re in, and pushing the genre forward with impeccable craft and an embrace of the WTF that makes it truly striking. On the eve of the film’s premiere in Park City, Garai spoke about what inspired her to move behind the camera, the technical elements that give the film its strong sense of dread and implementing her own ideas about a fairytale ending.

How did this come about?

I made a short which was in Sundance about six years ago and I had been working on follow-up features in a variety of different genres, but I found the conversations that people were having around horror, particularly at the low end of the budget spectrum, pretty exciting. There was a particular moment where things clicked when I had been reading a book about the prosecution of rape as a weapon of war. I had an idea for a horror film where you understand that the protagonist is somebody who has maybe got two very different sides to themselves – one side is very dark and they may be very shut off from it, and that is something I wanted to tie into the idea of the protagonist/hero saga and how heroes and films can often be very violent, but their violence is only ever a force for good. As most people know, violent people are very rarely people who only employ violence for good purposes, so I wanted to drill down into that a bit.

How did you find the right actors to have that much dimension in their performances?

I was very lucky with the cast. Our casting director suggested Alec immediately, and of course, I’d seen “God’s Own Country” and straight away I said that he would be perfect. The most important thing for that part was that you just meet him and you think this is an absolutely good man, that he has a sympathetic face and this gentleness to him as an on-screen presence that was absolutely vital. I couldn’t really afford to have anybody at any stage think, “This guy is a dubious character,” I really wanted to maintain a real sense around his innocence.

Then with Magda, I had a strong sense of what I didn’t want – somebody who I thought was going to feel very, very overtly modern in a way. She had to have something that felt timeless about her. We looked at a few different people, but I had seen “Wetlands,“ which was a amazing German film that [Carla Juri] made, and she was recommended to me and I saw “Blade Runner 2049,” [where] I thought she was really great in those scenes because often [that kind of] film becomes bigger than the performances, but I really remembered her. When I met her, she just really responded very passionately to the themes that the film was playing with in terms of feminism and I knew straight away that she would be absolutely extraordinary.

Imelda [Staunton] is someone I’ve worked with a few times as an actor and to be honest, I just never thought she would say yes, but I thought, “Well, I’ll ask her. I’ll put her at the top of my list and then I’ll just work down the list,” and she said yes. I couldn’t really believe it. I still can’t quite believe it, and it was amazing to have her come on and endorse it because after you get an actor like that, everybody thinks, “Oh, wow. Okay, now we have to do a really good job.”

Is there anything that you were able to do for your actors that you would have wanted from a director yourself?

Obviously, you just try and emulate the directors that you love and not the directors you’ve hated, then what’s difficult is, of course, that when you’re directing actors, you realize that every actor has a completely different sense of what makes a great director. You are emulating a director that you love, which may not be the same as another actor, so you come up against that quite soon. And to be honest, once you get to a certain level as an actor, it’s better to treat them as much as of a peer as possible to explain what you need from the scene and to elicit their help in getting that. That means you can talk to them in complex emotional terms about the story or the character or different acting techniques, and you can be very, very practical in terms of, “These are the story beats that I need to hit and I need your help and hitting them for these reasons.”

You can employ a combination of those two styles, which Is that if you just trust [the actors] and include them in the process, that that’s the best way. I have no desire to emanate those directors that feel the need to manipulate or terrorize or alienate or infantilize actors because I am one, so I didn’t have any weird shit that I needed to play out with them. [laughs]

The camera has real personality to it as well. What was it like working with your cinematographer?

We spoke a lot about making the film so it would have quite different personalities. The flashbacks have this lush fairytale [feel], there’s different lenses for the exterior London stuff, which feels very grounded in a reality and then the inside of the house has this very classic ’70s horror film feel, with lots of extreme and paranoid angles. Then there’s this idea of the forest having a much softer, more Gothic and more romantic feel to it. Then the idea of people dipping in and out of focus was something that we were always really happy with. We did a lot in the [color] grade to punch up the grain and make the film have this classic [sense] because it deals a lot with the idea of what the elemental hero is and an elemental figure who needs rescuing, so we wanted a fairytale quality.

What was it was like designing Magda’s house? I imagine that gave the actors a lot to work with as well.

It wasn’t easy. I went into the process quite naively thinking that the world must be just full of semi-derelict houses that you can just move into for a month, but in London, that is obviously not the case. It’s in the middle of a property nightmare, so we really struggled to find somewhere and we got really lucky in the end. Francesca, our designer, really toyed with the colors and repainted a lot, but all the fixtures and fittings were there. We could use the whole house and shoot it from every angle, so that made our lives a lot easier. As you say, it created a continuity in terms of what was in my head to what the actors were trying to build because the aesthetic of the film became very clear once everybody arrived on set. They could see that it was supposed to have this slightly retro and quite dreamy aesthetic to it and when we got on set and started filming that house, it did seem to really unify all the departments behind what the film was going to look and sound like.

It’s a wonderful score, one of those where it sounded like the sound design almost mixed into what music was. Was there that kind of cross-pollination?

Yeah, part of that just came from my own inexperience. I didn’t really understand that those two departments don’t necessarily always work together. As far as I understood it, the sound design that we were doing would become part of the conversation with the composition and I was really lucky to get this amazing composer, Sarah Angliss, who’s never composed for film or television before. We would just come in and play with different motifs and they would be in conversation with the sound design, and because a lot of her own work as a composer involves elements of sound design, that line wasn’t very clear to us. The one thing I said to her was that I really wanted to get a sense of the house being alive [with] the bells and the clocks and the telephones being swept up into the score.

I also really wanted to have some female voice [in there] – to record singers and to have choirs, but it’s difficult on a low budget. [Sarah] was amazing. She found incredible vocalists – a young girl and an older woman – and we have really beautiful female voices singing, which is something you don’t necessarily always hear in film because it’s often scored instrumental work. That’s something that I’m really proud of.

We’re speaking just before the film’s premiere at the festival, but have you seen this with an audience yet to know how effective some of those scares in the film are?

I haven’t yet in its finished state. I am very excited to and terrified because we had some test screenings, but there were only 25 or 30 people there, they were mainly friends and the movie wasn’t finished in terms of all the special effects and the score, so that feels like the most extraordinarily enormous gap between that and then sitting in a movie theater in front of hundreds of people watching the film premiere at Sundance. It’s obviously an incredible thing and I’m not complaining, but it’s also pretty terrifying as well.

So the scares are going to go both ways?

Exactly.

“Amulet” is now available on digital and on demand, which you can find here.