Tom Arden is a boisterous associate curator with the Metropolitan Museum of New York. He's intrigued by an embroidered cloth painted in a 16th century still life. In the process of interpreting a partial message, he becomes convinced that the cloth is the one mentioned in a legend involving Leonardo da Vinci. He sets his mind on finding the entire message, even if that leads him to a dangerous place.
Mahmut, a zealot and twenty-fifth generation caretaker of the hidden secrets of the old caliphate under Sultan Mehmed II, guards treasures on behalf of an imagined future Ottoman Empire. He believes that ISIS is the basis for this new empire and he will stop at nothing to prevent a powerful revelation on the cloth or its secret.
A murder prompts Tom to pursue a suspect, and a confrontation ensues amidst Roman ruins in Cyprus. There he battles the zealot in his attempt to fulfill his quest.