The story follows a young Jewish boy and his family as they move to Berlin. The mother wants them to show their place while many Jewish people within the community are in hiding. The rabbi suggests that they take in a young boy with mental health issues every weekend, so the boy can have a sense of stability within his life. They agree, and the family is matched with a boy who is 14 years old but matures slower than other children. Additionally, a worker at the mental institution notes that the boy is incredibly good at math. The siblings decide he should be matched up with the person closest in age to the boy. This leaves the boy paired up with one of the younger brothers. The younger brother thinks about how he is terrible at math and wishes that he wasn’t paired up with the boy. When the boy comes over to play, he does not enjoy the same types of games as the Jewish boy, and he is left feeling awkward. At night, the boy from the mental institution asks if the Jewish boy can ask him questions like what day of the week his birthday will fall on in a certain number of years. The boy agrees and asks these questions for a long time. Week after week, the boy comes back, and the Jewish boy begins to grow more attached. The boy learns he must move back to Paris and thinks about how he will tell the boy in the mental institution. Once he tells him the boy takes it well, and the Jewish boy thinks about how the other boy had a sense of assuredness and understanding of himself that he does not have.