This 1948 movie is one of at least four cinematic adaptations of Wilkie Collins' classic novel, not counting another three by the BBC - I particularly remember the 1982 series. I still like the book a lot, which could be considered one of the earliers examples of detective fiction, and is well ahead of its time in the way it uses multiple points of view. It's the story of art teacher Walter Hartright (Young), who is commissioned to tutor heiress Laura Fairlie (Parker), and her cousing Marian (Smith). But on the way to their house, he meets another young woman, who is a dead-ringer for Laura, and who he finds out, appears to have escaped from a nearby asylum. Walter falls for Laura, but she is already betrothed to another, and to spare her emotional punishment, Walter leaves his position. However, it appears her fiance, along with the manipulative Count Fosco (Greenstreet), may simply be after her fortune, and are prepared to go to any lengths to get it.
I think this is a case where the extended room available to a TV series probably works better than a book. This works well when setting up the various characters - John Abbott is particularly entertaining as the sickly and demanding fop, Frederick Fairlie, Greenstreet is as unctuous as you'd expect, and Parker (best known as the evil Baroness from The Sound of Music!) does well in separating the two characters she plays. However, once the machinations of the plot start to be revealed, the script feels like it is necessary to gallop from one twist to the next, with little opportunity to do more than put the necessary information over. The Gothic and horror elements which are so crucial to the novel's impact, are all but missing here, resulting in a lack of atmosphere as proceedings play out. Young is also disappointing as the story's hero: he's adequately square-jawed and noble, but brings little to the table beyond that. By the end, I was feeling an increasing desire to track down the 1982 version I mentioned, and see if that has stood the test of time any better.