During the restoration of the Malibran Theater in Venice, an ancient mummy of an Asian woman is discovered buried under the stage. Detective Antonio Galimberti and Professor Francesca Pavan, an expert in Chinese antiquities, are called to the scene. Two things are found on the a tiara of inestimable value and a diary. The only other lead they have is that the theater had been built on the foundation of Marco Polo's house.
The next day, the precious tiara is stolen from the forensic department and later the suspected thief is discovered dead—without the tiara. A murderer has it now. Eventually, two people who can identify the killer are also found murdered.
Antonio and Francesca are attracted to each other from the beginning, sparking a romance. But she has a dark the gift of retro-cognition, an ability to see a murder through an object that had belonged to a victim. In time, Francesca confesses to Antonio that when she had first touched the tiara, she had seen how the mummy died. And as she slowly translates the fragile diary, she identifies the Chinese woman, changing the pages of history.
Although the police recover the tiara, the murderer is still on the loose. But after holding a bloodied scarf worn by his last victim, Francesca recognizes the assassin. Antonio races to find the killer—but he is too late. The murderer has taken Francesca, leaving Antonio with only one clue to her the killer's bone-chilling last words, "Some secrets should remain buried."