"There was something inside [her] that wouldn't stop until the whole world was blood." The kingdom of Ostrova has been at war for centuries, and to feed the unending cycle of violence, every year, the day after the New Year, every sixteen-year-old in the realm is conscripted. A notoriously difficult exam called the Proving determines where in the military they will be placed. Norah Tasca is a peasant girl from Ostrova's oldest colony, Navaria. When she passes the Proving with a perfect score, she becomes only one of a handful of commoners ever admitted to the Citadel, the training program for Ostrova's future commanders. But at the Citadel, Norah is an outsider, and all is not as it seems. Those chosen to train there were not chosen for the intellect or their aptitudes, but for something else, something that challenges everything Norah has ever known about the world and the balance of power.