Joseph H. Lewis was one of the finest directors of film noir. This is surely his best.
It doesn't have some of the standard features of what we now call film noir. Though American-made, it is set entirely in England. It lacks gangsters. It lacks a femme fatale. It does not lack crime.
The title character answers an ad. She is overjoyed that she'll be making some money as a secretary. Instead, she wakes up days later as the pawn in a frightening plot. Only a very strong person could survive such a terrifyingly unsettling ordeal. And Nina Foch gives the sense of a strong woman as Julia.
Part of the excitement comes from casting against type: Ms. Foch has an elegant manner. She is no screaming, cowering victim. She is actually a bit icy and patrician, albeit impecunious. This makes her character's plight all the more believable.
Surely the single most fascinating element is the casting of Dame May Witty. She was (and is) probably most famous for the charming title character in "The Lady Vanishes." She has a sweet manner and a harmless, slightly dithering manner. But here she is far from a heroine.
George Macready is excellent as her extremely troubled son. The whole cast, in fact, is superb.
It seems that this famous and brilliant movie was made almost by accident. Undoubtedly the director knew exactly what he was doing. But he did it on a low budget. That is the thrill and charm of film noir, the real film noir: It is small, convincingly lowlife, and, in this case, unforgettable.

(Some possible spoilers)
I'm not too sure what Dreamworks was thinking when they decided to plunk $80 million down on this extremely tired and lame animated flick. They probably thought the spectacular animation would be more than enough to bring audiences (mostly families) to see it in droves. Well it seemed to work for the opening weekend, it made $26 mil., roughly and has made $38.1 mil. total (an estimation for this weekend). But I think audiences that came during the weekend saw pretty much the same thing I did, when I saw and they spread the word. This is one majorly lame movie, apart from the animation everything else, mostly the script seem to be done by a three year old.
The movie is only about 80 mins. long, but it feels like a three hour epic. A few sticking points for me are, well the irritating narration is one of them, and it's so obviously written. At one point he escapes from some captors and even though you can see the horse is obviously scared, up pops the narrator (the voice of the talented Matt Damon) to clear up any misconceptions (which would only happen in the simplest of mindsets.
Another one is the constant pop up of Bryan Adams songs, now I'm a fan of his music, I think he's good, but come on did Dreamworks really think audiences would be able to handle 8-9 of his songs throughout such a short movie, I certainly couldn't. Finally and here's a spoiler, a horse gets shot at point blank range by a member of the calvary, no less, she (the horse) then falls into a raging river, Spirit (the focus of the movie) tries to save her, but they both go over a waterfall that must have at least a 50 foot drop, well later in the movie near the end we see that this horse is alive and well. Now I know this is a kids movie, but even that little amount of realism is unacceptable.
To sum up, this is a really lame movie, I'm not saying kids won't enjoy it, but anyone else will be checking their watches just waiting for this tripe to end. Definitely on my Top 10 worst list of this year. -** out of 4 stars.