Mia Threapleton, who is the daughter Kate Winslet and British film director Jim Threapleton, makes her acting debut in Ireland-set chiller “Shadows,” directed by Italy’s Carlo Lavagna and mostly shot in an abandoned hotel in the woods near the village of Howth.

“Shadows” premiered last month at the Rome Film Festival’s Alice in the City section. The innovative pic combining psychological thriller elements, horror and coming-of-age tropes is centered on family dynamics in a post-apocalyptic world where a controlling mother, played by Saskia Reeves (“Luther”) and her two daughters, played by Threapleton and fellow rising young British talent Lola Petticrew (“A Bump Along the Way”), must avoid contact with daylight and its shadows in order to survive.

Shadows is produced by Andrea Paris and Matteo Rovere for Ascent Film with Rai Cinema, in coproduction with Feline Films. Vision Distribution is launching international sales at AFM.

Threapleton, who is 20, took questions from Variety about the challenges of her role as Alma, who has a fractious rapport with a mother whom she does not want to disappoint.

Playing Alma is an unusual debut. What drew you to the project?

I had just finished school, was free of exam hell, and felt excited, nervous and ready to start auditioning for things, and hoping that the opportunities to audition would come my way. I just hoped I would get the chance to do what I had wanted to do for so long!

“Shadows” was the first film I’d received an audition for, and the first script I had ever been given to read. I couldn’t believe my luck. I read it and didn’t put it down. Which is admitting a lot because I’m dyslexic and that means I have to read slowly and steadily to be able to absorb things fully sometimes.

“Shadows” is a genre film, yet the acting is naturalistic. How did you prepare for the role?

I read the script lots of times. I mean, really loads of times, over and over, because for me that is how a story goes in and stays in. I found that the more I read it, the more I found out about Alma and the easier she was for me to understand.

I tried to connect her deeper emotions to times where I may have felt the way she did. Frustration, a desire for independence, a need to be loved and taken care of. Fear. All normal things that teenagers tend to go through, I guess. 

Was it challenging to act largely in darkness? Or was this in a way helpful?

I don’t think I would say that it was challenging. In fact, it was quite a lot of fun. I loved it. I definitely think that it helped with the atmosphere during those scenes. It did help me to become more engrossed in the character; living as she would live, experiencing the night-time hours in her life, her world and feeling the threat of daylight as we would race to finish filming before the sun came up. It added to the desperation and mounting fears that the girls were supposed to feel.

Did you spend a lot of time on set while you were growing up?

I never actually spent much time around sets that my mum was working on. It was always a special treat. It’s a very different experience when it is happening to you, and not just something I was getting to observe from time to time. I really understand why my mum has always impressed on us how hard the work is. She is right! And I loved every second of it.