When diligent yet unappreciated clerk, Miya Isami, develops a new triangulation technique for map-making, her traditionalist superiors at the Imperial Cartographic Bureau heap scorn upon her. But when her novel approach exposes a swathe of missing land on the border between Scorpion and Lion Clan territories, Isami stumbles onto something far more significant than a mere mapping error. Her discovery offers the prospect of resolution to the seemingly endless territorial squabbling between the proud, warlike Lion and the secretive Scorpion. In a bid to contain the conflict, an Imperial Treasurer dispatches Isami with her fresh insights to the Spine of the World. Yet she is far from welcome in the mountains. She must negotiate between the clans, uncover the truth, and discover the location of a hidden valley before the fragile peace is shattered by war.