Spanish director Javier Fesser has sparked controversy and praise in equal measure for his third feature film, Camino, which delves into the curious world of Opus Dei as seen through the eyes of an 11-year-old girl. A favourite with both critics and audience alike at the San Sebastian film festival in September, where it had its world premiere, the film has gone on to perform well at the Spanish box office through Alta Films, taking just over $1m since its release on October 17.

The film is based partially on the life of Alexia Gonzalez-Barros who died in hospital in 1985 and became the focus of a cult of sainthood. Like Alexia, the film's protagonist, Camino, and her family are members of Opus Dei - the secretive Catholic organisation founded by Spain's recently canonised Josemaria Escriva - that encourages devotion to God without taking holy orders or retreating from the outside world.

"I heard about the case of Barros about 20 years ago," says Fesser. "After a few years, the process of her sainthood began and I got to know her story in detail. She appeared to me to be an extraordinary human being, which led me to get to know other similar cases of 'child saints' and above all awoke in me curiosity about the world of Opus Dei."

Writing the script proved to be a drawn-out process. "For years I turned the story over and over in my mind to find the best way to tell it, but it wasn't until 2004 that I submerged myself fully in the script, to which I dedicated two years," says Fesser. "In the end I succeeded in drawing together the necessary pieces to make what I really wanted to develop - an emotional love story."

The key focus is very much on Camino, played by newcomer Nerea Camacho, and how she copes with an authoritarian, pious mother; an impossible romance with a young boy in a theatre group; and eventually the trauma of her cancer treatment and subsequent retreat into a fantasy world.

Fesser's previous films have also explored life from a child's perspective or have been childlike in nature. His debut feature Mortadelo And Filemon: The Big Adventure (2003), a cartoonish comedy-adventure, took the Spanish box office by storm, raking in $28m (EUR22m). A year later he was nominated for an Oscar for his short Binta And The Great Idea, about a girl in a Senegalese village.

But despite his previous success, funding for Camino proved difficult to acquire. "It wasn't easy," Fesser concedes. "But once in progress the project absolutely awoke the interest of the industry here in Spain."

Spanish production outfit MediaPro decided to come onboard as a co-producer alongside Fesser's own company Peliculas Pendelton. "The collaboration and support of Television Espanola and the Icaa (Institute of Cinematography and Audiovisual Arts) were also pivotal to get such a risky project underway," says Fesser of the film's Spanish backers.

The $6.4m (EUR5m) film shot for 14 weeks on location in Madrid. Wild Bunch has sold it to territories including Latin America (Quality Films), Portugal (Lusomundo), Poland (SPI), India and the subcontinent (Alliance), and Malaysia/Indonesia (Karya Prima).