In an ancient empire covered by a nearly impassable mountain range, factions within and without threaten to topple a thousand-year-old peace. The Empire's survival depends on the unknowing and unwitting. Zornan is a simple man who works as a Peak Crosser carrying letters and small items amidst the empire's isolated valleys on his giant hawk. His idyllic life with his wife Calla and their daughters is shattered when a stranger frames him for murder. His only path to clear his name and return to his family is for Zornan to help the stranger's illegally born daughter Mairie reunite with her mother. As they flee over and under mountains, Zornan discovers that Mairie is not an innocent young woman, more monster than maiden. Pursued by the empire and its enemies and confounded by betrayal, each step hurls Zornan farther from his family and entangles him more with Mairie. Zornan's wife Calla is left to discover a way to cleanse her husband's sullied name, assisted by an imperial agent who is falling in love with her. All the while, the Emperor dispatches an earnest military scout named Mizcarnon to find Zornan and Mairie before rebels use them to shatter a crumbling Empire.