In 1720, a young Calusa Indian girl name Mara is kidnapped and dragged aboard Captain Hannah Dunne's pirate frigate, the Devil Ray. In the months that follow, Mara's journey takes her far from her Calusa village in Southwest Florida to the slave quarters of an indigo plantation in South Carolina. Along the way, Mara uses the ancient powers of the Calusa to calm a terrible storm at sea. She is taken to a pirate hideout where she learns about the infamous pirate Blackbeard. As a slave on a Charles Town plantation, she uncovers secret plans for a slave rebellion and is forced to make desperate choices. Finally, Mara makes the most important discovery of all: the value of her own freedom.