Loyal, self effacing service in England's far flung colonies has long been considered the patriotic duty of the Randolph family. Clive, the elder brother, has just returned home from a mission in the unsavory Gold Coast of Africa when his younger brother John balks at carrying on the familiy tradition. Convinced of his duty by his grandfather, Sir John, John enlists in the service and is sent to fill his brother's post in Africa. Much to Clive's dismay, he is also sent back to Africa to investigate the source of a series of radio broadcasts that are sewing unrest throughout the world. Because the government believes that Hugo Zurof, a man posing as a scientist while plotting to rule the world, may be linked to the broadcasts, Clive is ordered to keep his mission secret. In Africa, Clive enlists Carpenter, a district commissioner, to spy on Zurof's operations, and on the day that Clive receives an urgent message to meet Carpenter in the upcountry, Clive's pregnant wife Helen falls ill with the fever. Putting his duty first, Clive leaves his wife behind when Zurof appears and, desperate to prevent Clive from reaching Carpenter, Zurof convinces John to call his brother back. Clive, disgraced and recalled for dereliction of duty, returns to England while Zurof intensifies the campaign to instigate a world war. Ordered to Zurof's mine to investigate, John feigns drunkenness, breaks in on the broadcast and shouts a family code which his uncles hear in England. John's information leads a bombing mission, headed by Clive, to the site of the broadcast. When the planes are heard overhead, Zurof throws John out of the radio station just as the bombs hit their target. With the elimination of Zurof's threat to peace, the stain is removed from the Randolph name and the brothers win back their family honor.