Judd Nelson had the same reaction to the story of Elisabeth Fritzl as anyone: horror. But as a film actor, he found the tale almost beyond belief. "The story that it's based on is incredible," he told Nicki Swift, "If someone were to have written it, no one would buy it. They'd be like, 'Come on, man. This is ridiculous.'" And yet, it's not. "This happened," Nelson noted with evident fascination and horror, adding, "much worse than the movie portrays."

Nelson has also changed his mind about the wife of Josef Fritzl, Rosemarie, who helped raise some of the children born of incest in her own basement. "What I thought then was the mother's lying, there's no way the mother didn't know." But Nelson explained that from the calculated construction of the secret bunker to stocking it discreetly by shopping at different grocery stores, this diabolical villain methodically pulled the wool. "It's so tight, his plan, that no one suspects." Nelson added that Fritzl was also supposedly "very charming."

Nelson and director Elisabeth Rohm needed to transplant the story from Austria of the 1980s and excise some of the worst scenes for the censors. "There's so much we don't know, so it leaves it open for an interpretation for a script. But as long as you don't overstep what makes logical sense. Some stuff you have to make adjustments because it's TV. Some stuff you have to make adjustments because it's America."