A few decades after the end of the holocaust, Aldona is beside the woman who she called her mother for her whole life as she dies. Aldona hears her mother say "I love you" to someone who isn't there named Freddie. After her mother passes away in the bed, Aldona prepares to leave, but finds a tin filled with papers in it. They are letters, at the top one says "If found, please return these letters to 4th St, Apt 18, Bucharest, Romania." She reads them. During the Holocaust, a woman named Zina begins writing to the child of her sister, Naomi, as soon as she realized she would be born. She writes about how Naomi wanted to have the child no matter what. Zina was very happy to know she was pregnant, and thinks of how happy Naomi's betrothed would be to know that she is pregnant. She recounts how she and Naomi were suddenly taken by Nazis to a concentration camp, and how her betrothed tried to follow them as the Nazis drove them away. Naomi first tells Zina of the pregnancy, then tells another woman in the camp named Ruth, who tells her that she should end the pregnancy as it is dangerous, not only for her body, weakened by the abuse of the concentration camp, to endure the pregnancy, but if the Nazis found out they would be punished. But Naomi would not be convinced to abort. Naomi, Ruth, and Zina begin learning from the block supervisor at the camp, Gosia how to handle a birth an a child. Naomi and Ruth are skeptical about telling Gosia about the pregnancy, as Gosia is German and is there to redeem herself in the eyes of her Nazi superiors after she showed her Jewish prisoners sympathy at a different camp. Gosia has been rewarded for showing cruelty to other prisoners in this camp. Eventually, Naomi admits to Gosia that she is pregnant, and Dr. Gosia also tells her of the risks. But Naomi is determined, so Dr. Gosia decides to help. One day, Naomi, her sister, and Ruth are tasked by the Nazis to go through all of the things that were stolen from Jewish homes to find valuables. Dr. Gosia had told them of things they would need for the birthing process. They all try to steal something for this, and Naomi tries to steal a silver pin. Naomi is caught and badly beaten. When Naomi returns, Zina and Ruth are happy to see her alive and to know that they hadn't found out about her pregnancy. But Naomi is very injured from the beating. Naomi gives birth to a healthy baby girl named Aldona, but soon after dies. This sparks deep hatred for the Nazis in Zina, for taking her sister away. She resolves to make a better world for baby Aldona. Zina has to figure out how to take care of Aldona while she has to work, but luckily the camp is shut down and quarantined for a typhus outbreak, allowing Zina time to find someone to take care of Aldona while she is away working. Zina writes about all of the sweet memories of baby Aldona, like how she liked the pig and cow noises Ruth made to her, and how she had a robust cry. She writes about having to hide her and keep her from crying. She writes about how she wishes she could write to her parents about her birth. She writes about how she hears that Russians are coming to liberate them from the camp. There is another day of quarantine, so Zina is able to stay with Aldona for a while longer. But that same day, Ruth is selected for "transport" and must leave to a certain death. But Zina is determined to help Ruth, so she devises a plan to send word to Ruth's Norwegian friend through some French girls who will be able to send the word and get her off the transport list. Ruth was spared, and they are glad, while also being sad for those taken to be killed. Zina begins writing about all of Aldona's firsts, like her first bath. The typhus quarantine is over, and Zina and Ruth have to go back to work. But it is clear to them that Germany is losing the war as new women come in from camps that the Germans lost. As Aldona gets older and is almost a toddler, Zina writes about how hard Gosia and Ruth worked to help take care of Aldona. She talks about how many people in the camp know of Aldona and are helping too, but she is worried about the amount of people who know as there is more risk of being found out. One day, Zina gets word that nurse Gerda, the Nazi nurse who ends all pregnancies and kills children, is coming to check their block. All the women of the block helped Zina hide, and Gosia spoke to nurse Gerda as she said that she heard a baby was born on this block. Gosia plays dumb and asks where she heard that from, and Zina is happy to know that Gosia will cover for them. Aldona starts making noises, and it seems like Gerda hears it, so the women of the block begin to cough to cover the noise, and say that there is a cold going around. Disgusted, Gerda leaves. The block is joyous to have not been found out, but Zina knows they may not be as lucky next time. The next day, Gosia tells Zina that she knows a sympathetic German pharmacist named Paula who can take Aldona. Zina is afraid to give away Aldona, although she also knows that typhus and being discovered are big risks if she stays. But Zina decides to keep Aldona anyway. Another day, Zina writes that it seems someone is on their way to the camp, whether it be rescue or a black van coming to take them to be killed. She writes that either way, she wants Aldona to know that her aunties did all they could to keep her safe. That is all the writing that Aldona finds from her aunt Zina. She is shocked to find out that Gosia is not her mother, and that she is not German. She feels sadness for the women she never got to meet who did so much to make sure she survived. The landlord comes to let Aldona know that they are ready to take Gosia's body away. He asks her where he should direct her mail as she moves away from the home Gosia had for her. As she gathers her suitcases, Aldona tells him to direct it to Fourth Street, apartment eighteen, Bucharest, Romania.