Brittany Murphy as Elisabeth, the severely disturbed teenager who alone holds the key to Jessie’s release.

But the multi-layered story of the novel - which is, after all, what drew Kopelson and others to the project in the first place - remains at the heart of a pivotal scene: a tour-de-force of direction and performance in which Conrad finally unlocks the secrets in Elisabeth’s mind. Set in a subway station in Chinatown, it is made up of a mind-blowing 250 different shots, switching back and forth between past and present as Elisabeth faces up to the memory of her father being murdered by Patrick B Koster, the same man who is now holding Conrad’s daughter to ransom.

“She finally confronts the past and, in doing so, helps Nathan,” says the film’s director, Gary Fleder. “It’s a scene that straddles the line of being neither flashback nor present day. It blurs the lines, moving through time and space at that particular moment.”

Fleder was an obvious choice for the film. Like every astute moviegoer, Kopelson had noticed his directorial debut, Things to Do in Denver When You’re Dead, a thriller which melded a love of film noir with a modernist consciousness (and a ferocious cinematic skill), and did so a lot more skilfully than many of the movies by other young directors who became cult film-makers in the late nineties. When Fleder showed his ability to deliver a more straightforward action/thriller in Kiss the Girls, Kopelson knew he was the man for Don’t Say a Word.

For Fleder, an understanding of how Elisabeth had become the way she was was crucial before he could start working on the film, and he spent time with forensic psychiatrist Robert Berger. “I didn’t understand how she’d become a fragmented, psychiatric mess,” says Fleder. “I looked to Dr Berger to give us a real person, if you will: an honest pathology of a disturbed, threatened young woman. And he helped me see that one way Nathan might gain her confidence would be by showing her his own vulnerability: by persuading her to help him and his kidnapped child, Nathan is helping Elisabeth help herself. It demonstrated to me that the relationship between her and Conrad could be circular.”

But it was the spiralling, intriguing shape of the story that really attracted Fleder to Don’t Say a Word. “Movies have become increasingly slick and lacking in texture,” he notes. “I wanted to move away from this trend of slick, monochromatic settings. My directive to [director of photography] Amir [Mokri] and [production designer] Nelson [Coates] was, ‘I want to see the texture of people’s faces – of the tiles and of the paint peeling off the hospital walls. I want to embrace the shadows.”

In the end, though, Fleder is happy to admit that what really makes Don’t Say a Word work - what pushes it over the edge from interesting idea into full-tilt thriller - is the good old-fashioned chemistry of great performances. Brittany Murphy, who plays Elisabeth, is an actress Fleder himself introduced to Kopelson, after casting her as Janis Joplin in his (sadly) shelved biopic.

“She did a cold reading of a scene on tape that knocked everybody out,” says Fleder, who then screen tested the young actress with Douglas. “We knew then and there that no one else could do the role. Brittany really embodied Elisabeth’s mercurial quality, and her chemistry with Michael was extraordinary.”

Don’t Say a Word is, of course, in the final analysis, a Michael Douglas movie. And the scene where Nathan realises that his daughter is gone is, says Fleder, “an example of actor and camera collaborating to create a specific emotion. The power Michael has in this scene is the power of silence, of listening. The camera circles him in a predatory fashion, externalising his feelings of frustration, longing, despair and anger, and of being completely surrounded. Michael is not only one of the great stars: he’s one of the great actors.”