When Pope Alexander orders the courtesan Damiata to the remote fortress city of Imola to learn the truth behind the murder of his beloved son, Juan, she knows that failure comes at the price of her own child’s freedom. However, a string of gruesome murders have left Imola’s residents too gripped by fear to help a lone woman. Enlisting the aid of the obscure Florentine diplomat Niccolò Machiavelli and the eccentric military engineer Leonardo da Vinci, Damiata sets off to decipher the killer’s taunting riddles: she with her street smarts, Leonardo with his groundbreaking “science of observation,” and Machiavelli with his new “science of men.”