Detective Chris Bronson is stunned to learn that his best friend's wife has died after falling down the stairs at her villa in Italy. Arriving to support his friend, Bronson finds signs of a break-in on the front door of the villa, and above the fireplace, under a layer of fresh plaster, he discovers a built-in stone with a strange inscription in Latin. His instinct tells him that the woman’s death was not an accident and that the answer to the murder lies in this mysterious inscription. Bronson turns to his ex-wife, an expert in ancient history, for help, but their investigation suddenly becomes extremely dangerous. Some forces are ready to do anything to ensure that the ancient secret remains unsolved...