Isaac Bell of the Van Dorn Detective agency while sailing back from Europe saves a pair of inventers from attack by several ruffians. It later turns out that they have been working on a means to create talking movies and the Kaiser’s top agent is trying to steal the invention to make propaganda movies in preparation for WWI. Mad dashes back and forth the country by rail, perils of Pauline escapes, the dash across Germany to France by a young German girl working with a Van Dorn detective to deliver a message to Bell. Lots of fun in an older world with out our modern equipment, communications and travel methods. What can I say it’s a Cussler novel.