Along the Mediterranean coast, the Roman empire’s richest citizens are relaxing in their villas, enjoying the last days of summer. But the gorgeous weather belies impending doom, and only one man is worried. The young engineer Marcus Attilius has taken charge of the Aqua Augusta, the enormous aqueduct that brings fresh water to the people around the Bay of Naples. There is a crisis on Augusta’s main line—somewhere north of Pompeii, on the slopes of Mount Vesuvius. Attilius must repair the aqueduct before the reservoir runs dry. His plan is to organize an expedition in Pompeii. Attilius soon d