The Moon That Fell from Heaven

Ehli-nikkalu, eldest daughter of the Hittite emperor, is married to a mere vassal of her father. But despite her status, her foreignness and inability to produce an heir drive a wedge between her and the court that surrounds her. When her secretary is mysteriously murdered while carrying the emperor a message that would indict the loyalty of his vassal, Ehli-nikkalu adopts the dead man's orphaned children out of a guilty sense of responsibility.
A young cousin she has never met becomes a pretender to the throne and mobilizes roving armies of the poor and dispossessed, which causes the priority of her loyalties to become even more suspect. However, Ehli-nikkalu discovers a terrible secret that could destabilize the present regime if the pretender ever learns of it.
With the help of a kindly scribe, her brave young ward, and an embittered former soldier trapped in debt and self-doubt, Ehli-nikkalu sets out to save the kingdom and prove herself to her father. And along the way, she learns something about love.