Map on endpapers.

Jonathan Marcus, a young American lawyer and a former doctoral student in classics, has become a sought-after commodity among antiquities dealers, but when he is summoned to Rome to examine a client's fragment of an ancient stone map, he stumbles across a startling secret: a hidden message carved inside the stone itself. The discovery propels him on a perilous journey from the labyrinth beneath the Colosseum to the biblical-era tunnels of Jerusalem in search of a hidden 2,000-year-old artifact sought by empires throughout the ages.--From publisher's description.