Well-made political thriller. 1948 is the year Hollywood joined the anti-communist crusade, and there's no mistaking the bad guys-- Raymond Burr in a Lenin-like goatee, a sinister gathering of "comrades", and Hollywood's version of commie rhetoric about how the individual doesn't matter in the global scheme of things. Up to that point, the studios had been turning out generally pro-Soviet films in behalf of our WWII allies. But now, turning on a dime, we find out what perfidious characters we had been supporting. Oh well, as they say, in politics there are no permanent friends or enemies, only permanent interests.
Square-jawed Dennis O'Keefe makes for a dogged and intrepid FBI agent aided by Scotland Yard loan-out Louis Hayward. Together, they show what sterling fellows the English-speaking world turns out. They're on the trail of a covert Soviet spy sneaking out secrets from what is likely a bomb designing laboratory, though it's never specified. The plot rather prophetically anticipates the Klaus Fuchs affair of 1949, when the German-born spy was exposed as smuggling A-bomb secrets to the Soviets as early as 1945.
The suspense revolves around who the lab spy is and how he's getting the secrets out. It makes for entertaining, if workman-like, viewing. The familiar narrator Reed Hadley lends stentorian authority, along with some fine location photography. Together they impart a sense of reality to what are otherwise standard stereotypes and a melodramatic plot. Sure it's Hollywood's manipulative brand of political cinema, this time turned on our former friends. But at least it's watchable, minus the kind of cold-war hysteria that came to characterize other efforts of the period. All in all, an interesting and revealing reflection of its time.