Doctor Nikola meets Gilbert Pennethorne, an ordinary man whose life has gone downhill. He was tricked by his former boss who stole information about the location of a gold mine. Gilbert is determined to take his revenge while Nikola sees a great opportunity to become wealthy. He manipulates Gilbert into assisting him in the new evil scheme he has come up with.

Guy Boothby was an Australian author who lived in the period 1867-1905. His earlier works described life in Australia, but he gained wide popularity with his later fiction, which offered a vivid combination of crime, science fiction and horror stories.

Boothby is well known for his Doctor Nikola series, a collection of novels telling the story of an occultist who seeks immortality and world domination.

Other popular stories by him are "A Prince of Swindlers", which tells the story of a thief, and "Uncle Joe's Legacy and Other Stories", which is a collection of ghost stories. All in all, Guy Boothby left the world a colourful and rich literary legacy.