An American reporter covering the war in Europe gets mixed up in the assassination of a Dutch diplomat.

Disgusted by the publicity handouts that his foreign correspondents have been wiring in as news stories, the editor of the New York Morning Globe assigns crime reporter Johnny Jones to deliver the hard facts from Europe. Using the name Huntley Haverstock, Johnny voyages to London to interview Van Meer, a Dutch diplomat who has committed to memory a secret critical clause in the Allied Peace Treaty. In London, Johnny also meets Stephen Fisher, the head of a pacifist organization, and his daughter Carol. Becoming suspicious when Van Meer fails to appear to deliver his speech on how to avert war, Johnny follows the diplomat to Amsterdam. In the pouring rain in Amsterdam Square, Van Meer, who doesn't seem to know Johnny when the correspondent greets him, is shot on the stairs, and his murderer disappears in a sea of umbrellas. In pursuit of the murderer, Johnny meets Carol and ffolliott, a British correspondent, and they follow the assassin's trail to a windmill in the Dutch countryside. After sending ffolliott for the police, Johnny discovers a drugged Van Meer held captive by the Nazis, and learns that the man who was shot on the stairs was an imposter. Before ffolliott can return with the authorities, however, Van Meer's captors spirit him away, and when the police arrive, they refuse to believe Johnny's story. Refusing to abandon his search for Van Meer, Johnny returns to London where, while visiting Fisher, he recognizes one of the men from the windmill. Realizing that the pacifist must be a Nazi agent, Johnny teams with ffolliott to rescue Van Meer. When war is declared between England and Germany, Carol and her father escape aboard a clipper bound for America, only to discover that Johnny and ffolliott are on the same flight. When the plane is shot down, Fisher, realizing that he faces arrest, sacrifices his life to save the others, who are rescued by an American ship. Once safely on board the vessel, Johnny is banned from wiring the story to his paper, but he subverts the captain's orders by giving the details under the guise of a personal phone call and soon becomes America's voice from Europe.