Ten-year-old Flavia and her friends encounter the Roman admiral Pliny before making a journey to her uncle's farm near Mt. Vesuvius, where they try to solve a riddle, reunite a family, and get out of the path of a natural disaster.
Flavia and her friends go to Rome to celebrate the Festival of Jupiter at Senator Cornix's town house, where they befriend the young charioteer, Scopas, and quickly find themselves embroiled in a campaign to sabotage one of the rival racing factions.
Flavia and her friends return to Rome from Ephesus in the year 81, and when they learn about the mysterious death of Emperor Titus, they investigate, leading to many changes for Italia and for themselves.
Eleven-year-old Flavia and her friends Jonathan, Lupus, and Nubia are invited to visit Pulchra, who asks them to uncover who is trying to poison her mother.
Flavia, Jonathan, Nubia, and Lupus work together within the rules of the ancient Roman legal system to prove the innocence of Hephzibah, a slave in a wealthy household who has been accused of murder, but the witnesses are killed before they can testify before the magistrate.
Suspecting their friend Jonathan is alive, Flavia, Nubia, and Lupus go to Rome for the Colosseum Games, facing wild beasts, criminals, conspirators, and gladiators, and where Nubia is called upon to make a terrible choice.
Jonathan and his friends are called to Rome by the emperor in the winter of 80 A.D. to find the new Prometheus believed to have brought an epidemic to the city, but Jonathan, obsessed with reuniting his parents, makes some unwise--and life-threatening--choices.
In 80 A.D., ten-year-old Roman sleuth Flavia and her friends sail from Corinth to Rhodes to try to stop a mysterious man who is kidnapping children and selling them into slavery.
