In the future, there will be a library where women can check out human babies like books. At the circulation desk, hopeful women browse a selection of babies for days or weeks. All women are given a genetic screening at the age of sixteen, which determines their suitability for procreation. Those who do not have optimal genetics are barred from having children. The women who check babies out from the library are almost always those who have been deemed unfit to have children themselves.

Hadley, a young unlicensed woman who lives a solitary life, comes to check out a baby from the Omaha Public Library, where she bonds with a baby girl named Gemma. Hadley reflects on her loneliness and lack of family ties as she ponders motherhood and tries to take good care of Gemma. Meanwhile, a wealthy woman named Seraphina, who, despite being licensed and having children of her own, hates being a mother and has no love for her kids, bemoans her life of constant childcare. She usually leaves her children in the care of two nannies, Gabriella and Chloe, but they have gone on vacation. Seraphina suspects Gabriella and Chloe are lovers and expresses her jealousy at their happiness.

Later, visitors come to Hadley’s home. Suspicious, she opened the door and found Gabriella and Chloe. They tell Hadley that they rescue borrowed babies and share the horrifying fate of the children who are kept at the library; library babies are the illegal offspring of licensed men and unlicensed women, and when they age out of the library program, they are sold into slavery. Hadley, now desperate to save Gemma and wrapped up in Gabriella and Chloe’s cause, takes Gemma and travels with the couple through the rural farmland of the Dakotas and into Minnesota.

During a stop in a small town, Hadley runs into a police officer who suspects her of illegal activity. He asks to see her and Hadley’s papers for identification, but Hadley quickly escapes. The women flee the town and head further East. When they reach Thunder Bay, Ontario, they stop at a small house where four other women are waiting, one of whom is Gemma’s birth mother. After seeing Gemma return to her mother and reminiscing about her childhood, Hadley is offered the chance to help rescue other babies. She contemplates the idea of being free for the first time.