Dora is a retired schoolteacher who makes her living at Rio de Janeiro's Central Station by writing letters for those unable to read or write. Life has left her feeling bitter and impatient, so much so that she sometimes stashes away or even destroys the letters she composes. Among her clientele is the mother of Josué, a needy 9-year-old boy with dreams of meeting his estranged father. Tragedy strikes when his mother dies in a bus accident, leaving Josué homeless, which ignites a sense of responsibility in Dora. She initially traffics him to a corrupt couple but is soon overwhelmed by guilt and reclaims him.
Despite her hesitations about taking on this new responsibility, Dora ultimately decides to accompany Josué on a journey to northeastern Brazil in search of his father. In an attempt to distance herself from him, she tries to abandon Josué on a bus, but he follows her, leaving behind his backpack containing her money. Facing poverty, they encounter a generous, evangelical truck driver, who soon abandons them after Dora encourages him to drink beer and becomes overly friendly. In dire circumstances, she trades her watch for a ride to a place called "Bom Jesus do Norte," a fictional representation of Cruzeiro do Nordeste in the Sertânia district of Pernambuco.
Upon reaching Bom Jesus, they discover Josué's father is missing; the current inhabitants reveal that he won a lottery for a house and left. Out of options, Josué suggests that Dora write letters for the many visitors arriving for a significant pilgrimage, which provides them a lifeline. They venture to where the settlements are located, but upon arrival, they learn that Josué's father has vanished without a trace. Josué promises to wait for him, but tired of the uncertainty, Dora offers him a more stable life with her. She reaches out to her friend Irene back in Rio, asking her to sell off her appliances and furniture, reassuring her that she’ll call once they're settled.
After hanging up, Dora realizes they cannot leave until the morning. Near the bus stop, she meets Isaías, one of Josué's half-brothers, who invites them to dinner. They encounter Moisés, another half-brother, and learn about their father Jesus and the family's tumultuous history. Isaías shares a poignant letter from their father stating he intends to find Josué and Ana, his mother, who has long since moved to Rio. In the letter, he expresses his desire to reunite their family. As she reads, Dora reflects on Josué, saying, > "and Josué, whom I can't wait to meet." While Isaías and Josué cling to the hope their father will return, Moisés harbors skepticism.
The following morning, while they are deep in sleep, Dora slips away to catch a bus back to Rio, forgetting the letter from Jesus and the one she never mailed from Ana, which expressed a longing to unite the family. Josué awakens too late to stop her, and both Dora and Josué are left with nothing but the photographs taken to remind them of one another.
