Among the monuments of a Rome in full summer, two men and a woman are following clues to uncover a secret that has been kept safe since the times of the Emperor Constantine. A nun that committed a mortal sin, a professor that studies the past, and a colonel of the Italian Carabinieri in charge of protecting it. At the same time, in the maze of the streets of the eternal city, two brotherhoods that have been enemies since the dawn of glorious Rome are keeping track of their every move.
