While testing out one of his many airships, Tom needs to make emergency landing for repairs. He complains of the poor quality platinum used for his magneto, and is overheard by an escaped Russian exile. The man tells Tom of a secret platinum mine, deep in Siberia. The man also explains that his brother is still in exile, and will be more useful in locating the mine. Tom organizes an expedition to save the exile and find the platinum mine.It is to note that the Russian revolutionaries in the book are referred to as the Nihilist movement. However, given the time in which the book takes place, the author would more likely have been referring to Bolsheviks.