When filmmaker Bernadett Tuza-Ritter met 52-year-old Marish, a Hungarian factory worker and maid, she was drawn to her haggard face - one that seemed as if it belonged to a much older woman.
Tuza-Ritter asked if she could film Marish's life, factory by day and househelp by night, for a few days to make a five-minute film. But those few days turned into 18 months as the director slowly understood the dark reality she was capturing.
"I'm not sure there was a moment I realized my film was uncovering modern slavery; it was a gradual process," said the director of "A Woman Captured" — an 85-minute documentary about domestic slavery screened at the Sheffield Doc Fest this week.
"My eyes are open now and it will be impossible to keep them closed again," she told the Thomson Reuters Foundation at the U.K. premiere of her film, which was featured at Sundance in January.
The documentary closely follows the life of Marish, a single mother who has been trapped for more than a decade as an unpaid domestic worker in Hungary by an abusive employer called Eta.
One of millions of women worldwide enslaved in domestic servitude - through physical or psychological coercion - Marish sleeps on a sofa, only eats leftovers, and is forced to take out loans for her boss and hand over her wages from the factory.
In the film, Marish yearns to be reunited with her teenage daughter who had been driven from the house by Eta years before.
"Happiness is not for me," she tells Tuza-Ritter on camera, which remains almost entirely fixed on Marish during the film.
Eta - who has two other maids employed in similar conditions - allows the filmmaker into her home in exchange for payment and in the belief that she has nothing to hide or be ashamed of.
"It's not like she's under control," Eta says in the film - off-screen as her face is never revealed - explaining how she provides Marish with food, cigarettes and a roof over her head.
Despite her initial hopelessness, Marish grows in confidence through her bond with Tuza-Ritter and the film culminates in her escape by night and an eventual reunion with her young daughter.
"I felt responsible for her and I felt guilty," Tuza-Ritter said at Britain's biggest documentary festival. "I know documentary filmmakers talk of observational filming, but that was impossible."
Anti-slavery activists hope the film will shine a light on the hidden nature of domestic servitude and modern slavery - an industry that affects an estimated 40 million people worldwide.
"The heart-breaking story of Marish shows the reality of millions of women trapped in slavery across the world ... All too often, slavery is also hidden in plain sight," said Klara Skrivankova of London-based charity Anti-Slavery International. "We should look closely around us and be aware that domestic slavery - coercion and violence - can be happening next door."