Flavia, Jonathan, Lupus, and Nubia-friends and detectives-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!