In the remote village of Ndotsheni, in the Natal province of eastern South Africa, the Reverend Stephen Kumalo receives a letter from a fellow minister summoning him to Johannesburg. He is needed there, the letter says, to help his sister, Gertrude, who the letter says has fallen ill. Kumalo undertakes the difficult and expensive journey to the city in the hopes of aiding Gertrude and of finding his son, Absalom, who traveled to Johannesburg from Ndotsheni and never returned. In Johannesburg, Kumalo is warmly welcomed by Msimangu, the priest who sent him the letter, and given comfortable lodging by Mrs. Lithebe, a Christian woman who feels that helping others is her duty.
Kumalo visits Gertrude, who is now a prostitute and liquor seller, and persuades her to come back to Ndotsheni with her young son.
A more difficult quest follows, when Kumalo and Msimangu begin searching the labyrinthine metropolis of Johannesburg for Absalom. They visit Kumalo's brother, John, who has become a successful businessman and politician, and he directs them to the factory where his son and Absalom once worked together.
One clue leads to another, and as Kumalo travels from place to place, he begins to see the gaping racial and economic divisions that are threatening to split his country. Eventually, Kumalo discovers that his son has spent time in a reformatory and that he has gotten a girl pregnant.
Meanwhile, the newspapers announce that Arthur Jarvis, a prominent white crusader for racial justice, has been murdered in his home by a gang of burglars. Kumalo and Msimangu learn that the police are looking for Absalom, and Kumalo's worst suspicions are confirmed when Absalom is arrested for the murder. Absalom confesses to the crime but states that two others, including John's son, Matthew, aided him and that he did not intend to murder Jarvis.
With the help of friends, Kumalo obtains a lawyer for Absalom and attempts to understand what his son has become. John, however, makes arrangements for his own son's defense, even though this split will worsen Absalom’s case. When Kumalo tells Absalom's pregnant girlfriend what has happened, she is saddened by the news, but she joyfully agrees to his proposal that she marry his son and return to Ndotsheni as Kumalo's daughter-in-law.
Meanwhile, in the hills above Ndotsheni, Arthur Jarvis's father, James Jarvis, tends his bountiful land and hopes for rain. The local police bring him news of his son's death, and he leaves immediately for Johannesburg with his wife. In an attempt to come to terms with what has happened, Jarvis reads his son's articles and speeches on social inequality and begins a radical reconsideration of his own prejudices.
He and Kumalo meet for the first time by accident, and after Kumalo has recovered from his shock, he expresses sadness and regret for Jarvis's loss. Both men attend Absalom’s trial, a fairly straightforward process that ends with the death penalty for Absalom and an acquittal for the two other defendants. Kumalo arranges for Absalom to marry the girl who bears his child, and they bid farewell. The morning of his departure, Kumalo rouses his new family to bring them back to Ndotsheni, only to find that Gertrude has disappeared.
Kumalo is now deeply aware of how his people have lost the tribal structure that once held them together, and returns to his village troubled by the situation. It turns out that James Jarvis has been having similar thoughts. Arthur Jarvis's young son befriends Kumalo. As the young boy and the old man become acquainted, James Jarvis becomes increasingly involved with helping the struggling village. He donates milk at first and then makes plans for a dam and hires an agricultural expert to demonstrate newer, less devastating farming techniques.
When Jarvis’s wife dies, Kumalo and his congregation send a wreath to express their sympathy. Just as the bishop is on the verge of transferring Kumalo, Jarvis sends a note of thanks for the wreath and offers to build the congregation a new church, and Kumalo is permitted to stay in his parish.
On the evening before his son's execution, Kumalo goes into the mountains to await the appointed time in solitude. On the way, he encounters Jarvis, and the two men speak of the village, of lost sons, and of Jarvis's bright young grandson, whose innocence and honesty have impressed both men. When Kumalo is alone, he weeps for his son’s death and clasps his hands in prayer as dawn breaks over the valley.