Dirk Bogarde plays one of those 'reluctant spies' so common to adventure films of the 1960s. A poverty-stricken author, Bogarde is sent to Czechoslovakia by the British government as an unofficial 'goodwill ambassador' to an industrial firm. It soon dawns upon him that his real assignment is to gather facts for his government's secret service; unfortunately, neither Bogarde's bosses nor his adversaries let him in on just how much danger is involved.