The unnamed narrator returns to his hometown, Wad Hamid, a small village near the Nile in northern Sudan, after studying in British poetry in London for seven years. He is glad to be back, but the village has changed since he left--most importantly, there is a new arrival, a mysterious middle-aged man named Mustafa Sa'eed. The narrator is unnerved by Mustafa and asks his family and friends about the man. Eventually, the narrator's grandfather reveals that Mustafa is from Khartoum, adding that he is a good farmer and neighbor but keeps to himself. He moved to Wad Hamid five years before, and married Hosna bint Mahmoud. Later, Mustafa visits the narrator at his home, introducing himself but remaining coy about his past.
The narrator is at a drinking session with his friend Mahjoub, who sees Mustafa walking by and pressures the older man to join them. Mustafa reluctantly does, and as he gets drunk, he begins to recite poetry in English. The narrator is shocked by this, and approaches Mustafa the next day asking where he learned to speak English. Mustafa initially insists that the poetry was drunken gibberish, but the next morning he returns to the narrator. Mustafa Sa'eed says that if the narrator swears he will tell no one, he will reveal his life story. The narrator eagerly agrees.
As a young boy growing up in Khartoum, Mustafa was a genius and quickly advanced through elementary school, which was all the education that was available in Sudan at the time. Although he was poor and fatherless, the headmaster of his school arranged for him to attend secondary school in Cairo, where his school’s headmaster, Mr. Robinson, mentored him. Upon graduating, Mustafa was awarded a scholarship to Oxford, and quickly became the darling of the English literary and political scenes. He associated mainly with left-wing bohemians, although he secretly resented their silly misconceptions about "Oriental" culture. In fact, he exaggerated his African roots, making up stories about living in the jungle and charming snakes. This proved to be a very effective way of seducing women, and Mustafa became very promiscuous, promising to marry women and callously then callously breaking it off. Three of his girlfriends—Ann Hammond, Sheila Greenwood, and Isabella Seymour—committed suicide after Mustafa Sa'eed broke their hearts. However, Mustafa's twisted relationships with women culminated in his marriage to Jean Morris, a cruel and manipulative woman that he eventually murdered. He was imprisoned for seven years, and left England upon being released to live a simple farm life in Sudan.
The story returns to the narrator's perspective. He reveals that Mustafa Sa'eed disappeared during a flood. Although the villagers believe his death was an accident, the narrator privately speculates that Mustafa killed himself. Two years later, the narrator accepts a job at the newly formed Ministry of Education in Khartoum. He remains preoccupied with Mustafa's story for the next 25 years. He meets a variety of people in Khartoum, many of whom knew or heard of Mustafa Sa'eed. He also hears a variety of political opinions from his colleagues. He quietly disagrees with all of them, but does not speak out about his own opinions.
Although the narrator spends most of his time in Khartoum, he returns to Wad Hamid whenever he can get time off. After a long period away, he returns to the village, which is making fitful attempts at modernization. Some young people are demonstrating for the National Democratic Socialist Party, but most of the villagers are cynical and believe the government will never do anything to help people like them. We learn that the narrator has been made the executor of Mustafa Sa'eed's estate and the guardian of his wife, Hosna bint Mahmoud, and their two sons.
The narrator goes to visit his grandfather, who is drinking with his friends Bakri, Wad Rayyes, and Bint Majzoub. Bint Majzoub is a striking character; well into her eighties, she drinks and smokes like a man, and she likes to chat and make explicit jokes about sex. The men and Bint Majzoub banter about sex, and debate the virtues and drawbacks of female circumcision. Bint Majzoub supports the practice, because she believes it makes women work harder to please their husbands. Wad Rayyes comes down against it, citing theological arguments, but ultimately his opinion comes down to the fact that he prefers having sex with uncircumcised women. Bakri insists that the issue is blown out of proportion and does not matter either way, and the narrator and his grandfather are both quiet during the debate. After the guests leave, the narrator's grandfather reveals that Wad Rayyes is planning to ask the narrator for Hosna's hand in marriage.
The narrator is uncomfortable and angry that he has been asked to make choices for Hosna, whom he believes should decide for herself what to do. He goes to visit her, asking what she thinks of the proposal. Hosna adamantly rejects it, saying that she will never remarry, and if she is forced to, she will kill the husband and then herself. The narrator contemplates how beautiful she is. The next morning, Wad Rayyes inquires how the narrator's visit went. The narrator advises him to drop the proposal since Hosna is not interested. Insulted, Wad Rayyes angrily insists that he will marry Hosna anyway, since her father and brothers have already agreed to the union.
The narrator asks his friend Mahjoub for advice. Mahjoub laughs off the dilemma, saying that the narrator cannot change the social order of Wad Hamid, and Wad Rayyes will probably die soon anyway. Mahjoub also suggests that the narrator marry Hosna; this would resolve the situation and would make sense since he is already the guardian of her boys. The narrator is ambivalent about this, but as he leaves Mahjoub, he realizes that he is in love with Hosna.
The narrator does not intervene in the marriage, and decides to take a truck back to Khartoum instead of a boat. On the way, he becomes delirious from heat and thirst. He sees a group of soldiers who are on the way to arrest a tribal woman who murdered her husband. That night, the narrator and his driver rest with several other truck drivers. They dance and drink together, and he enjoys the impromptu party.
One month later, the narrator receives a telegram from Mahjoub with the news that Hosna is dead. He returns to Wad Hamid but the villagers are reluctant to tell him what happened. He eventually finds out the story from Bint Majzoub, whom he plies with whiskey. She reveals to him that Hosna's father beat her until she agreed to marry Wad Rayyes. The marriage was tense and Hosna refused to consummate it, much to her new husband's frustration. One night, Bint Majzoub heard screams coming from Wad Rayyes's house. She assumes that Hosna finally agreed to have sex with him and screamed in orgasm. As the shrieks go on, though, she becomes annoyed, then concerned, and enters the house when Wad Rayyes calls for help. She discovers the old man's body. Hosna has stabbed him to death. She lies dead on the floor also, with a knife in her heart and many bite marks all over her body.
Some of the women had tried to hold a funeral for Hosna, but Mahjoub, by now the mayor of Wad Hamid, banned it, saying that she did not deserve remembrance. The narrator confronts him about this and Mahjoub stands by his opinion, further insulting Hosna. The narrator attacks him, but is pulled away before he can strangle his friend.
The narrator wakes up after having fainted. He is consumed by grief and anger, and goes to Mustafa Sa'eed's house, opening the private room that has remained locked since Mustafa Sa'eed's death. The room is filled with English books and photographs of Mustafa's English mistresses. A portrait of Jean Morris hangs in a place of honor above the fireplace. The narrator recalls more of Mustafa's story, which was left out in his account at the beginning of the book. We learn more about his relationship with Jean Morris, who took pleasure in humiliating Mustafa and destroying his possessions. We find out that Mustafa murdered Jean Morris by stabbing her to death as they had sex, and she seemed to derive pleasure from being killed.
The narrator is disgusted that Mustafa never truly left his past behind, and considers burning the private room. However, he decides that doing so will not help anything, and instead goes to swim in the Nile. He contemplates allowing himself to drown, but is seized by a sudden desire for a cigarette. He decides that he would rather live, because he wants to spend more time with the few friends he has left, and take care of his duties in life. He swims toward the shore and begins to call for help.