In 1792, formerly enslaved Benjamin Honey and his Irish wife, Patience, discover an island where they can make a life together. Over a century later, the Honeys' descendants and a diverse group of neighbors are desperately poor, isolated, and often hungry, but nevertheless protected from the hostility awaiting them on the mainland. During the tumultuous summer of 1912, Matthew Diamond, a retired, idealistic but prejudiced schoolteacher-turned-missionary, disrupts the community's fragile balance through his efforts to educate its children. His presence attracts the attention of authorities on the mainland who, under the influence of the eugenics-thinking popular among progressives of the day, decide to forcibly evacuate the island, institutionalize its residents, and develop the island as a vacation destination. Beginning with a hurricane flood reminiscent of the story of Noah's Ark, the novel ends with yet another Ark.