Mira, her older brother Malcolm, and her photographer father are traveling the world to document the Modern Wonders - and search for Mira's missing mother. While visiting Paris, the family receives a postcard from their mother sent from Rome. The postcard gives Mira instructions for when she next time-travels; an ability Mira has inherited from her mother. When they arrive in Rome, Mira is transported to the 16th century in the disguise of a boy. Mira is befriended by the painter Caravaggio and other artists and scientists. But this is an era where many are suspicious of forward thinking individuals. Mira's instructions from her mother are to try and protect her new friends from the evil Madame Lefoutre. If she succeeds she and her mother can be reunited.