In order to free her parents from the government that runs the walled compound called the Enclave, Gaia cracks a code her parents left her, a code that reveals the real parents of all the babies forcefully adopted from outside the Enclave to diversify the genetics of their population. Gaia Stone is a young girl with burn-scars disfiguring her face, who has to perform the duties of a midwife for the people who live outside the Enclave. The Enclave is a place where food is plentiful and everyone lives in comfort. Outside the Enclave, where Gaia lives, the world is a dry and barren wasteland. In exchange for food and medical supplies, those who live on the outside must give up the first three newborn babies they give birth to each month. The babies will apparently be given the privilege of being adopted by well to-do citizens of the Enclave. Most mothers willingly give their babies, hoping that their children will grow up in happier conditions. Many mothers still resist, however, and their babies must be taken away by force.
The story starts with Gaia collecting the first three babies of the month from their mothers to advance to the Enclave. When she returns to her house, she finds out that her parents have been arrested by the Enclave for keeping track of advanced babies and their birth parents. Her parent's friends, who have inside knowledge of the goings on of the Enclave, tell Gaia that her parents are kept prisoner and are to be executed the next week. Gaia is devastated. She finds a note in her pocket with a piece of code written on it she believes her mother was trying to communicate some important information with her but she doesn't know how to crack the code. Her mother also left her a length of ribbon which Gaia thinks may be in code as well.
With the help of her parents' friend, she sneaks into the Enclave to save her parents. While Gaia is in the Enclave, she witnesses an execution of a couple who have illegally decided to be together. Every marriage in the Enclave is carefully planned because the Enclave is obsessed with maximizing genetic diversity and preventing marriages that could propagate certain undesirable genetics. The woman is executed but she was pregnant. Gaia risks her life to perform a quick surgery to save the baby and she is caught by the Enclave guards and imprisonned.
Gaia learns from the captain of the guards Captain Grey that the population inside the Enclave is diminishing due to more mothers being barren. She learns that the Enclave take the babies from the population of people living outside the walls to keep their population stable and diversify genetics. The Captain explains that the Enclave had previously forbidden midwives to track lineages of babies that enter the Enclave because they were afraid that the children would try to seek out their birth parents. Now, however, the Captain explains that the Enclave needs to know the parentage of their children so that they can essentially breed children based on favorable genetics and "breed out" bad diseases like hemophilia. The Captain tries to convince Gaia to help him crack the code her mother left behind but Gaia refuses because she doesn't trust the Captain and also because she doesn't know how to crack the code. Gaia is kept imprisonned, perhaps to use as leverage against her mother but also for her exceptional skills as a midwife. She and another midwife (who is also a prisoner) travel around the Enclave on various errands but have to return to their prison cell each night.
Gaia and Captain Grey soon develop a friendship. Captain Grey is forced to carry out his duties even though he doesn't necessarily believe in the way things are run in the Enclave. He tells Gaia that they have discovered that her ribbon is indeed a code of some sort. Captain Grey tells Gaia that higher ups are going to interrogate her soon and if she doesn't prove useful they will kill her. In her desperation, Gaia tells him that her mother puts a tattoo pattern of freckles on the feet of each baby that is taken away to the Enclave. Gaia learns that Captain Grey is actually the son of the Protectorat, who is essentially the leader of the Enclave. Apparently he was disowned and relegated to guard duty due to a mysterious "crime against the state".
The next day, Gaia is brought to be questioned again, and her new interrogator threatens to kill her parents if she doesn't cooperate by solving the code on the ribbon. When Gaia refuses again, her new interrogator shows her footage of her father being released from the Enclave. She sees her father trying to run into the wasteland but get shot down by a soldier. She is devastated at her father's death and the potential death of her mother. The interrogators bring her to a room where she will spend her days until she can crack the code.
Gaia finally manages to crack the code on the ribbon. Meanwhile, Captain Grey promises that he will help her escape the Enclave, but apparently the time is not right and he leaves her. Later, Gaia finds out that many people are looking to know who their birth parents are including the sergeant who guards her cell. After secretly exchanging information, Gaia discovers to her surprise that this Sergeant is one of her brothers taken away to be advanced to the Enclave when he was born. The Sergeant helps her to escape and find her mother.
Gaia finally manages to escape the prison and make it to her parents' friends home. Her parents' friends tell her that they have been watching the area where they think her mother is kept and they thought they saw her inside the tower cell. They also tell her that the Sergeant her brother has escaped the Enclave and gone to a place called the Dead Forest which is a refuge somewhere in the wasteland that surrounds the Enclave. Gaia disguises herself as a boy and with the help of one of the midwives of the Enclave as well as Captain Grey, she formulates a plan to sneak into the prison tower where her mother is kept.
Gaia successfully reunites with her mother in the tower and tries to find a place to hide her until the guards give up trying to find them. Gaia finds out her mother is pregnant and she has to help her mother give an impromptu birth to her new sister a girl that she names Maya. Because of the lack of medical supplies, her mother passes away. She mourns her mother's loss but is determined to save her new baby sister. Captain Grey helps her by showing her a secret tunnel so that they can escape. Unfortunately, the tunnel exits are known to the Protectorate. One branch of the tunnel leads to a bar which may be guarded and another leads to a nursery, where all the babies of the Enclave are kept. Gaia and Captain Grey decide to go to the nursery where they will be able to find formula to feed baby Maya.
Captain Grey comes up with a bold plan to get them out by pretending they aren't fugitives but wealthy nobles with every right to roam the streets. They disguise themselves in expensive clothing and approach the wall. They almost escape but are discovered and Captain Grey sacrifices himself so that Gaia and Maya may escape. The story ends with Gaia taking Maya to the Dead Forest where she believes other fugitives are hidden.
Best part of story, including ending:
I like that the story illustrates the interesting dynamic between mothers who were willing to give up their children to the Enclave in the hopes that the children will be well taken care of vs. mothers who think that motherly love is more important than living in comfort, surrounded by wealth. Gaia's parents believed the latter and so they burned Gaia's face when she was born so that she would appear disfigured and the midwives wouldn't take her away and give her to the Enclave. Gaia initially resents her mother for snatching away her opportunity but later on understands that there she is lucky to have known her birth parents. Many of the adopted children in the Enclave feel lost and their foster parents don't truly love them because such children are used more as tools for genetic diversification.
Best scene in story:
My favorite scene was when Gaia helped her mother give birth to Maya in the prison tower. It was a very sad scene because her mother passes away after giving birth, but at the same time it was also a hopeful scene because Gaia was re-energized by her mother's last hopes that she can take her new sister and escape the Enclave.
Opinion about the main character:
I like that Gaia was crazy enough and courageous enough to enter the Enclave to save her parents even though someone with her disfigurement would easily be spotted as an infiltrator from outside. It was because of her courage that Captain Grey fell in love with her and helped her to fulfill her mission.