John Marlowe (Douglas Fairbanks Jr.) is an American surgeon visiting England when he is decoyed to Vosnia, a small European country. He finds that he is to operate on the Vosnian dictator. The dictator dies but is replaced by a look-alike. As one of the few who know, Marlowe is hunted by the country's secret police.
Marlowe flees and seeks the help of Lisa Robinson (Glynis Johns). They are pursued across the country and are on the point of escaping when she is shot. Marlowe could escape but stays.
The head of the secret police, Colonel Galcon (Jack Hawkins) arranges a "shooting accident" for Marlowe, but, as Marlowe walks outside to his fate, the false dictator is heard making a live speech on the radio. Shots are heard and Marlowe goes back inside the building. Galcon confirms by telephone that the stand-in has been assassinated.
Marlowe and Galcon discuss the situation and Galcon realises that it may be over for him. As the people have seen the "dictator" die, it is no longer necessary to have a cover-up. Marlowe and Robinson are released and fly to freedom