The novel is a story of both personal and political tragedy in the fictional Central American country of "Boca Grande".

The novel is narrated by Grace Strasser-Mendana, an American expatriate who married into one of the three or four families that dominate Boca Grande politics, the Mendanas.

Grace was trained as an anthropologist under Claude Lévi-Strauss, and later took up the amateur study of biochemistry, both attempts to find clear-cut, scientific answers to the mysteries of human behavior.

Both attempts fail: Grace remains uncomprehending and cut off from the people around her, and in the final line of the novel she admits, "I have not been the witness I wanted to be.

Charlotte's beloved daughter Marin has run off with a group of Marxist radicals and taken part in an absurd act of terrorism, and in the wake of her daughter's disappearance, Charlotte's marriage to a crusading Berkeley lawyer (not Marin's father), has fallen apart.