The story takes place in England in the mid-1930s. During the Silver Jubilee of King George V and Queen Mary in May 1935, the entire British Royal Family is killed in a freak accident after the explosion of a large dirigible (similar to the Hindenburg disaster), and the search is on to find a surviving heir of British blood. After an extensive search, the choice falls on Jack Green, a 24-year-old stage actor who, unbeknownst to him, is the grandson of the philandering Prince Albert Victor, Duke of Clarence and Avondale, George V's elder brother, and the nearest living heir. He is virtually kidnapped and brought to Buckingham Palace, where he is placed in the care of William Millingham (known as Willie) who is to be his Private Secretary. Millingham assists the new king over the initial period of adjustment to his new status. He is duly installed as King John II.
The 1991 film King Ralph is a loose, comic adaptation of the novel. John Goodman stars as Ralph Jones, an American lounge singer who improbably becomes the British king.