Sable Ursu has just turned eighteen, which means she is ready to breed. Within the confines of her world, a patriarchal cult known as the Den, female fertility and sexuality are wholly controlled by Men. In the season they come of age, Sable and her friends Mamie and Dinah are each paired with a Match with the purpose of conceiving a child. Sable is paired with Ambrose, the son of a favoured Man in the Den. Others are not so lucky. In their second trimester, girls are sent to the Birth Yard, where they are prepared for giving birth and motherhood, but are also regularly drugged and monitored by their midwives. Sable is unable to ignore her unease about the pills they are forced to swallow and the punishments they receive for stepping out of line. Too many of the girls, including Mamie and Dinah, have secrets and it is impossible to know whom to trust. When Sable's loyalty is questioned and her safety within the Den is threatened, she must rebel against the only life she has ever known-- the only life she has been designed for.