Accustomed to the luxuries of a Minneapolis high school, Harriet Freeman, a sixteen-year-old African-American girl, goes to live with her mysterious great-grandmother on an enchanting island off the coast of South Carolina. Harriet is at first shocked and dismayed by the poverty-stricken, lethargic life on the island. Adjustment is difficult, but Granny helps, and so does Richard Corwin, an intelligent African-American boy studying to be an agricultural expert.