It's 1916, and German saboteurs have damaged or destroyed munitions factories in the United States in anticipation of the U.S. entering World War I. In the fishing village of Seacrest, Maryland, two murders are blamed on the Klu Klux Klan. Sixteen-year old David Knox doesn't accept the sheriff's ruling and conducts his own investigation. Meanwhile, a new bomb-making factory is scheduled to open in Seacrest and Maryland's governor is expected to attend the ribbon-cutting ceremony. David suspects a saboteur is responsible for the murders and a real threat exists against the factory, and possibly against the governor, and he must convince the authorities before the factory dedication.