Pisa. During works in a train yard where the ancient port of the city once was, an Egyptian ship dedicated to the goddess Isis is found in the hold of a Roman ship. A ship inside another ship. A sensational discovery that could change the interpretation of the link between the cult of Isis and imperial Rome. To evaluate this exceptional find, the University of Pisa calls on John Cartridge, a world famous archeologist, who happens to be in Tuscany about to take a cruise in the Mediterranean with a group of friends. What was supposed to be a carefree holiday is changed into a treasure hunt with the players scattered all over the world. Because Cartridge certalnly can't back down and, on his own, can't interpret all the unknowns regarding the most important archeological find of the times. The help of his 'traveling companions' will be fundamental: the surgeon Hans Müller, the young archeologist Alessandro Bertolucci, the lawyer Rebecca De Roberto and, especially, the anthropologist Michelle Valmont, expert in arcane symbology. But someone else has eyes on the mysterious ship of Isis: Erik Rein, leader of a secret sect, wants to have the ship at any cost in order to complete a plan as insane as it is horrifying. A plan that involves his blood relatives. After Il segreto dei custodi della fede, another electrifying story for enthusiasts of archeological thrillers: macabre objects of worship, esoteric rituals, initiations, amulets and forbidden love in a race against time that will change the fate of its protagonists forever.