Stavia, the novel's heroine, is the younger daughter of Morgot, an important member of the Marthatown Council. The book opens with Stavia as an adult, heading for a meeting with her fifteen-year-old son, Dawid. He has spent the last ten years living outside the city walls as a warrior, as all boys do, and is now old enough to decide whether he wishes to remain a warrior or accept a life of study and service among the women. Dawid formally renounces his mother and chooses to become a full-fledged warrior.
Afterwards, Stavia remembers when her own brother was sent to live with the warriors. Much of the rest of the novel is told in flashback, and follows Stavia's life from childhood to adulthood. Meanwhile, in the story's present, Stavia prepares for her role as Iphigenia in Marthatown's annual performance of Iphigenia at Ilium, a reworking of the Greek tragedy The Trojan Women that weaves through the novel as a leitmotif.
When still a child, Stavia met Chernon, the son of one of her mother's friends. Although Chernon lives in the garrison with the other boys and men, he and Stavia form a friendship. They meet at the twice-annual Carnival, the only event in Women's Country where men and women can mix freely. Stavia eventually agrees to smuggle books to Chernon for him to read, even though this is forbidden for boys in the garrison.
In fact, Chernon has been ordered by his commander, Michael, to learn more about the secrets of the women who rule Women's Country. Stavia leaves Marthatown for several years to train as a doctor, but on her return Chernon pursues their relationship again. When Stavia is selected for an exploration mission to the south, Chernon takes a leave of absence from the garrison and meet her there.
While away from Women's Country, Stavia and Chernon are captured by a band of "Holylanders", members of a struggling community to the south of Women's Country. They practice polygamy and seem to be descendants of rural fundamentalist Christian and Mormon splinter groups. The Holylanders are brutally misogynistic and treat women as slaves to their husbands.
Stavia's experiences among the Holylanders give her a deeper appreciation for her homeland, but upon her return to Women's Country she finally learns the secrets of the Women's Country Council and the choices they have made to preserve their way of life.
The question of the causes of human violence is also a major theme, and in the novel Tepper's society believes they are successfully breeding violence out of humanity. In the novel, violence appears to be biologically determined but not sex-linked. Large numbers of hysterectomies and other societal manipulations mean many women do not contribute to the genetics of the next generation. By selecting only nonviolent males to breed, the society is slowly increasing the number of such nonviolent males.