American double agent David March (Robert Goulet) lives in Germany during World War II and poses as a traitor in order to infiltrate the Nazi machine. While working to destroy a secret weapons plant, March still finds time for romances with a beautiful German scientist (Eva Pflug) and a sultry French singer (Christine Carère). This action-packed drama combines three episodes of the 1966 television series "Blue Light" into a feature-length film.