I've read the reviews written before writing my own, and I'm astonished by the low ratings and the reasons for that.
I didn't know the story, didn't know (anything about) Nellie Bly. But the movie showed all it had to.
The movie might not be of the best quality, you might expect more given all the digital techniques these days. But I kind of appreciate it, because it accentuates the time these things actually did happen.
I've seen reviews which said that Christopher Lambert seemed to be there mostly to give the movie 1 known actor, and that Caroline Barry did not such a great job at playing faking a mental illness. I don't agree on both statements.
Lambert hadn't the main role, he simply had the role of the main physician. He showed a man who, I think honestly, tried to figure out how to help his patients, but got terribly confused about what's right and wrong in how to realize that. Which has been sort of "good practice" for a pretty long time in medicine...
Barry played the main role, a woman who acts being mentally ill, in a time people hardly understood what mentally ill meant. Today's psychiatrist en psychologist would definitely not fall for the show she put on. We won't either. But back than? Don't forget, it's incredibly hard to fake a mental illness with our current knowledge, back than she could very well succeed with what Barry showed us on screen. Mainly because that was what a lot of men those days would expect from a mentally ill woman.
It is precisely that, what makes this movie a very catchy story that won't let go of you until the end. As a viewer I felt the unease, the emotions, the pressure, like it was choking me.