1881: The electric lights of Paris have been extinguished. The Naturalist revolution is over. Adelaide was on the losing side. Once the Royal Scientist Doctor for the now-dead cyborg monarchs of France, she's now a fugitive, hiding from the new king's Police Sécrète. Pregnant and alone, she seeks refuge in a Parisian hospital but things have changed there too. What was once a cathedral of Science is now a bastion of ignorance and superstition. The battlefield veterans whose Augmented prosthetics she once created are shunned by the new regime and come to the hospital for her help. But her nemesis, the father of her child, has returned to France and threatens to reveal her illegal activities to the authorities. Can Adelaide repair her Augmented patients without losing her freedom ... or her life? The Vitruvian Mask continues the story of Adelaide Coumain, the Roboticist of Versailles, that began in The Archimedean Heart.