Ten-year-old Tabitha wanders the marshes of her small coastal village and listens to her father's stories about his pirate voyages and the mother she never knew. Since the loss of his wife, Helen, John has remained land-bound, but when Tab contracts yellow fever, he takes her aboard a sloop bound for Bermuda, hoping the salt air will heal her.

Years before, Helen herself was raised by a widowed father. Asa, the devout owner of a small plantation, gives his daughter a young slave named Moll for her tenth birthday. Helen gradually takes over the running of the plantation, but when she meets John, the pirate turned Continental soldier, she flouts convention by falling in love. Moll, meanwhile, is forced into marriage with a stranger. Her only solace is her son, Davy, whom she will protect with a passion that defies the bounds of slavery.