The Only Ones is set in a post-apocalyptic, dystopian future that has been destroyed by several pandemics that ravaged the entire world, causing mass destruction and infertility. Readers are quickly introduced to a resourceful woman named Inez, who has managed to survive the pandemics because she is immune to them. In the language of the world of The Only Ones, she is a "clean," or a person who has never been ill from the pandemics, making her, and her genetic material, invaluable. As such, she is coveted by people across the world who think that she could hold the key to saving humanity.
To make a living, Inez capitalizes on her rare status by selling her blood, skin, and hair to laboratories that service wealthy individuals wanting to produce healthy offspring—something which they otherwise would not be able to do. Although Inez makes good money selling parts of her body, the process is laborious and precarious. Inez is often not able to keep up with the demand for her products because so many want to thrive and conceive.
One day, Inez talks with one of her clients. They give her a unique proposal: iInexchange for a certain amount of money, Inez will provide the parents with genetic material and will carry the child to term for them. Initially, she approaches the situation with some trepidation, but ultimately agrees to the arrangement and gives birth to a baby girl wwhomInez names Ani. However, after seeing the child, the client refuses to take her, causing Inez to become a mother—a role she neither expected nor wanted.
Both Ani and Inez continue to face the challenges of their oftentimes harsh and unrelenting world. Together, they learn about themselves and the world. But Ani's birth changes Inez. She changes, and her dynamic with her new daughter changes too.
Eventually, Ani and Inez's relationship strains, and Ani briefly leaves Inez. When Ani returns, the reunion is tense but also revelatory for both women. After the reunion, the story ends with a tacit understanding between tthe wo women. Inez knows that Ani will follow her path; Ani accepts Inez for who she is.
