Reformed crook, Boston Blackie Dawson, accidentally comes into possession of the Romanov jewels, which the Grand Duchess Tatiana and her friends have brought to the United States for safety. Terrorists in search of the jewels transfer their attention to Dawson, but he is able to capture them with the aid of new electronic equipment and to expose Count Ivan as their leader. When Dawson gives paste copies to the U. S. Government, which also seeks the smuggled jewels, and returns the originals to their owner, Tatiana and Count Orloff are free to find happiness.