The story takes place in the United Kingdom 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 during a period of adjustment to his new status. He is duly installed as King John II.