Henderson, a troubled middle-aged man, decides to go to Africa to escape the complications and sadness that plague him at home. Henderson is a large man, often bumbling and loud, with a surprising physical appearance and great physical strength. He has a distinguished family, and his father, a famous author, left him three million dollars when he died. He is a World War II veteran and a pig farmer, but has a secret desire in his heart to become a doctor. His first wife, Frances, laughs at this desire.

Henderson is plagued by a voice inside his heart that says, I want, and he seeks salvation from and satisfaction of this longing in a number of ways, through playing the violin, drinking, shouting at his wife, but none make him feel better. He believes his wife Lily fails to live in reality, although Henderson believes he is on good terms with reality. One day, while he is shouting at Lily, his housekeeper has a heart attack and dies. Wracked with guilt and shame, Henderson decides to go to Africa with his childhood friend Charlie Albert and his wife. Henderson is fifty-five when he buys his ticket.

In Africa, Henderson finds Charlie's traveling style too pampered, and decides to take leave of Charlie and his wife and set off on his own with Romilayu as a guide. Henderson and Romilayu travel for many days until they reach the Arnewi tribe. The Arnewi are a kind and gentle people, but they are plagued by frogs in their water reservoir that have rendered the water undrinkable. Their beloved cattle are dying of thirst. Henderson wins the respect of their prince, Itelo, by wrestling him, and then meets the Queen, a wise and wonderful woman who teaches him about the desire to live, "grun-tu-molani," Henderson loves the Arnewi and is determined to rid them of their frogs. He builds a bomb to kill the frogs in the cistern, but ends up blowing out the cistern wall and draining away all of their water supply. Henderson is heartbroken that he has bumbled his good intentions so miserably.

Henderson next goes to the Wariri tribe, where he befriends the king, Dahfu, and becomes the Sungo, or rain king, when he lifts a heavy idol during the rain ceremony. Dahfu tries to help Henderson end his suffering by forcing him to spend time with his lion, Atti, and teaching Henderson to emulate her. Dahfu also tries to share with Henderson his belief that a connection exists between the inside and outside appearance of people, and emotions and characteristics are physically manifested. A faction of the Wariri led by a priest named Bunam disapprove of Dahfu's activities with the lion, and they try to use Henderson to manipulate the king. When Dahfu dies trying to capture his lion he believes hold the spirit of his father, Henderson, as Sungo, automatically becomes the next king. Heartbroken over the death of his friend, and distrustful of the Bunam's faction, Romilayu and Henderson flee the Wariri. Henderson takes with him the lion cub, which according to Wariri tradition now holds the spirit of Dahfu. On the journey home, Henderson takes care of an orphan boy who is traveling alone. Henderson has realized that the meaningful relationships in his life have been founded on love. He has also decided to follow his dream and enroll in medical school.