Flavia, Jonathan, Nubia and Lupus–the four friends from The Thieves of Ostia–sail to the Bay of Naples to spend the summer with Flavia’s uncle, who lives near Pompeii. There they uncover a riddle that may lead them to great treasure.

Meanwhile, tremors shake the ground, animals behave strangely, and people dream of impending doom. One of the worst natural disasters of all time is about to happen: the eruption of Mount Vesuvius!

This second in a series of Roman mysteries follows the children as they travel by sailboat, explore vineyards, and celebrate a Roman festival on the beach at Herculaneum in A.D. 79–not realizing they are in terrible danger. Will they solve their riddle? And more importantly, will they survive the volcanic eruption that buried Pompeii?