1866. In a coastal village in southern England, Nell picks violets for a living. Set apart by her community because of the birthmarks that speckle her skin, Nell’s world is her beloved brother and devotion to the sea.

But when Jasper Jupiter’s Circus of Wonders arrives in the village, Nell is kidnapped. Her father has sold her, promising Jasper Jupiter his very own leopard girl. It is the greatest betrayal of Nell's life, but as her fame grows, and she finds friendship with the other performers and Jasper’s gentle brother Toby, she begins to wonder if joining the show is the best thing that has ever happened to her.

In London, newspapers describe Nell as the eighth wonder of the world. Figurines are cast in her image, and crowds rush to watch her soar through the air. But who gets to tell Nell’s story? What happens when her fame threatens to eclipse that of the showman who bought her? And as she falls in love with Toby, can he detach himself from his past and the terrible secret that binds him to his brother?