Sir Richard Hannay introduces this last adventure involving his old friends. John Blenkiron discovers that a ruthless industrialist is plotting to destabilise America and cause global turmoil. Although Bavarian born, Castor plans to dominate the world from Olifa, a small country in Latin America. Hannay realises he is now too old for the job of thwarting these evil designs and enlists the aid of his old friend Sandy Arbuthnot, now Lord Clanroyden. Fortunately, Sir Archibald Roylance and his wife Janet are honeymooning in Olifa and are able to lend a hand. Sandy decides that revolution is the way forward and Buchan draws on his experience of the tactics of the Boers in South Africa to describe the action of the campaign. Also, the villain is captured and Janet is instrumental in effecting his ideological change but at great cost. The novel was published in 1929. It is unlikely to be a coincidence that in the same year American financial markets collapsed giving another Bavarian national, who had been abusing his people, the opportunity to consolidate his power in Germany and, ultimately, make his insane bid for world domination.