The Roman Mysteries: The Pirates of Pompeii: Book 3 by Caroline Lawrence
AD 79, following the eruption of Mount Vesuvius and the destruction of Pompeii. Among the thousands of people huddled in refugee camps along the Bay of Naples are Flavia Gemina and her friends Jonathan the Jewish boy, Nubia the African slave-girl, and Lupus the mute beggar boy. Their discovery that children are being kidnapped from the camps - among them the daughter of the powerful Publius Pollius Felix - leads them to solve the mystery of the pirates of Pompeii. A terrifically exciting and dramatic story and a brilliant picture of the aftermath of a great disaster.