Are the remains of Saint Peter buried in Rome, beneath the basilica that bears his name? Novelist Mara needs the proof in order to write her latest book. Her research leads her first to Jerusalem-and back into the life of Israeli professor Uri Nevon. Mara and Uri are together again, this time on a journey that will have them investigating the ruins and churches of Israel, and revealing hidden, shocking secrets beneath Vatican City-all the while carefully navigating a mutual attraction that threatens to derail their entire mission.

Meanwhile, a foe lurks in the shadows, watching their every move: members of a clandestine group with a chain of command that extends all the way to the Pope himself. They have reasons to keep the truth of Saint Peter buried. So as Mara and Uri dig deeper, the group resorts to desperate and violent measures, proving that they'll stop at nothing to prevent the truth from being revealed-a truth that could put the whole world in jeopardy.