Martins had spent five years researching the immigrant communities in Great Yarmouth, drawing heavily from real experiences to shape the script. The film's stark aesthetic, with its decadent seafronts and haunting marshlands, paints the town almost as a character in itself. It juxtaposes decayed remnants of tourism with the harsh realities of exploitation, creating an environment where survival is both physical and emotional.
The actors, including Beatriz Batarda, underwent immersive preparation, working alongside real factory laborers to embody their roles convincingly. This method added a visceral, physical layer to the performances, particularly in how the characters moved and interacted with their grim surroundings.
The director's focus on atmosphere extended to the inclusion of symbolic elements, such as a birdwatcher who bookends the story. This figure, observing migrations in nature, subtly parallels the movements of human migrants within the narrative. Martins has cited influences from conspiracy thrillers and expressionistic cinema to create an unsettling yet hypnotic tone.
The shoot faced unique challenges, as it began in March 2020, just as the COVID-19 pandemic struck. After an initial three-week filming period, the production paused for six months, forcing the team to adapt under immense uncertainty. This interruption heightened the tension and pressure within the cast and crew, infusing the film with a palpable sense of unease reflective of its themes. Martins even mentioned that this period influenced the emotional weight carried by the actors in the film.
Beatriz Batarda and Nuno Lopes have shared the screen in several notable projects, showcasing a dynamic on-screen chemistry. This chemistry likely stems from a shared commitment to authenticity, a deep mutual respect, and their previous experiences of working together on emotionally challenging material. Their ability to seamlessly inhabit their roles and convey complex emotional interplay has made their collaborations stand out in Portuguese cinema and TV. Their collaborations include Alice (2005), Saint Georges (2016), Menina (2017), Sara (2018), Viver Mal (2023).