This is a series of linked short stories involving what may be the world's first female diabolical criminal mastermind, Madame Koluchy. Norman Head had as a young man met Madame Koluchy in Naples when he became involved in a secret criminal society known as the Brotherhood of the Seven Kings. When Head discovered the sinister nature of the society he determined to have no more to do with them. He has since been living as a virtual recluse, amusing himself with scientific experiments. Now their paths have crossed again, and Head realizes this will be a duel to the death. Madame Koluchy is also a scientist, and a doctor. Her miraculous cures having made her a celebrity while her charm and beauty have made her the darling of English society. With the aid of his friend Dufrayer Norman Head is determined to bring this woman to justice. Madame Koluchy uses her medical skills to gain the trust of her victims. They then find themselves the victims of blackmail, robbery, kidnapping or worse crimes.