Dora, an ex-schoolmistress, has fallen on hard times and is now a public letter-writer at Rio Central Station. Ana and Josué, her son, are two of Dora’s clients. Josué has never seen his father and is hoping to trace him through the mails. Back home, Dora and her neighbor Irene go through the letters she wrote and choose their fate. Some she mails, others she simply throws away. Most, including Josué’s, end up in a drawer. Then Ana and Josué come to see Dora to send another letter. As they leave, Ana is hit by a bus and dies. At first Dora is unmoved by the boy’s distress, but finally she decides to help him find his dad.