When Cornelia joins Napoleon's army as a traveling naturalist with the power to heal, she meets the sister she never knew existed on the opposite side of the battlefield and together, they must use the magic of flowers to solve the mystery of their mother's death, while fighting for their survival. In the midst of the Napoleonic Wars and the rise of the floriography craze in Europe, two sisters separated at birth are bound together by a secret language of flowers passed down to them by the mother they never knew. When Cornelia leaves her cruel uncle’s home to join Napoleon’s army as a traveling naturalist, her ability to heal any wound and bring soldiers back from the brink of death earns her praise from higher-ups—and exposes her to those who would exploit her powers for themselves. Meanwhile, Lijsbeth lives in indentured servitude, her only respite her time spent flower arranging. When she meets a young English soldier and falls in love, Lisjbeth must decide whether to flee the clashing of two great armies at Waterloo or risk everything by staying. As the English and French armies collide in Waterloo, the sisters finally cross paths on opposite sides of the war. With the sisters reunited on the battlefield, they must work together to solve the mystery of their mother’s death and their father’s disappearance, all while surviving the war raging around them.