[1] Based on a book by Will Berthold, the film depicts the mission of a German spy Erich Gimpel during the Second World War to discover how far the American nuclear programme had progressed.

The film's sets were designed by the art directors Hans Kuhnert and Paul Markwitz.

Hiding out in a seedy New York hotel, Gimpel tries to find leads to scientists working on the nuclear programme, but his cover is blown when Cole defects back to the FBI.

Gimpel at last gets through to a scientist, who tells him that he is too late as nuclear bombs will very soon be ready to drop on America's enemies.

The death of President Roosevelt is followed by the customary moratorium on executions, so his penalty is commuted to life imprisonment.