Unisnpired and boring. Despite James Mason's best efforts to keep a face that might suggest a film noir, the story never gets going and the cast, especially the female lead (Joyce Howard) is a pain in the eye to look at. Instead of focussing on the spionage themed story, the plot focusses on whether the female lead trusts the hero or doesn't. Thus, the movie involuntarily feels like a screwball comedy, despite trying so hard to be full of tension. There is all but on twist in the movie, and you can see it coming when the opening credits role, that's how obvious it is. Stay away from it. Unknown for a reason.