Tristan has no identity, no face, no family, no rights. He is a perfect spy: an artificially created human whose metamorphic DNA can be programmed with "masques"--genetic copies of anyone--over and over again. Until his body breaks down. But Tristan"s masters offer him humanity, citizenship, and a permanent shape in exchange for one last mission. Now, Tristan must play a masquerade that will save--or destroy--an entire people.