Thirteen-year-old Kyra has grown up in an isolated community without questioning the fact that her father has three wives and she has twenty brothers and sisters, with two more on the way. That is, without questioning them much---if you don't count her secret visits to the Mobile Library on Wheels to read forbidden books, or her meetings with Joshua, the boy she hopes to choose for herself instead of having a man chosen for her. But when the Prophet decrees that she must marry her sixty-year-old uncle---who already has six wives---Kyra must make a desperate choice in the face of violence and her own fears of losing her family forever.