Waiyaki, the only son of Chege, a well-known and respected elder in Kameno, grows up in a time of tension between the tribes of the two ridges Kameno and Makuyu. Many areas of Kenya are experiencing the influx of the white man, and particularly the white man’s religion of Christianity. The major British figure in the area is Livingstone, who opened a notable mission school at Siriana. His most fervid convert is Joshua.
Joshua is a religious hardliner who even disowns his daughter Muthoni when she follows her own conscience and is circumcised, a practice condemned by the Christians for being “pagan” but which is central to the identity and culture of the tribe. Her sister, Nyambura, is a Christian and disapproves of Muthoni’s choice, but still loves her; Joshua, on the other hand, disowns his daughter.
After the procedure, Muthoni's health declines; soon, she is in a critical condition. Even though Waiyaki manages to get her to the hospital, she dies soon after.
Waiyaki is seen as a natural leader with a fire in his eyes that makes people obey. One day, Chege leads him to the top of a holy hill where he reveals a prophecy: Being the last of a long line of seers, Waiyaki must lead and save his people. Chege sends Waiyaki to Siriana so that he gains vital knowledge of the white man, but he warns him not to adopt their ideology.
Waiyaki obeys his father, and in the years after his father’s death, he builds a number of schools in Kameno. Many people are filled with a zealous desire for education and begin to admire Waiyaki as the savior who will enable the tribe to become independent and empowered. As for Waiyaki himself, he often feels that he is caught somewhere in the middle: while he is loyal to the tribe, he mostly desires unity and does not think everything the white man brings is evil.
However, Waiyaki soon faces the opposition of the elders of his tribe—particularly Kabonyi, who was once a follower of Joshua but later defected. Kabonyi considers himself to be the rightful leader of the people as he is older, and he also hates Waiyaki because he knows of the prophecy and fears that Waiyaki may be the chosen one.
As tensions rise between the ridges, Waiyaki and Nyambura encounter each near the river a few times and begin to fall in love even though they know no one would approve of them. Waiyaki asks her to marry him, but she refuses even though she loves him. One time when they are together, Kabonyi’s son, Kamau, glimpses the two; he is jealous of Waiyaki and vows to destroy him.
In an attempt to reconcile the two opposing groups, Waiyaki meets with Joshua, which alienates the elders of his own tribe, as they fear that he would sell them to the white men. However, the outcome is the opposite of what he expected, as both parties are fighting more fiercely than ever for their ideologies. Kabonyi takes advantage of Waiyaki and Nyambura’s relationship and calls a meeting to humiliate and disenfranchise Waiyaki, which he hopes will end his leadership.
Waiyaki and Nyambura pronounce their love for each other, and Joshua tells Nyambura she is no longer his daughter.
Waiyaki sees what is happening to his leadership after the Kiama kicks him out as a teacher. He visits the sacred grove to find clarity and realizes he should press for action. He now knows that education is not all that the tribe needs: they must have unity to push for political power.
Waiyaki leaves the grove and comes before the people. He makes his case but Kabonyi deems him a traitor and when he brings Nyambura forth, Waiyaki cannot deny her. This is proof to the people of Waiyaki’s oath-breaking.
In the end, the people of Waiyaki's tribe are more loyal to the elders than to him. The council of the elders punishes Waiyaki and Nyambura, but the nature of their punishment is not revealed.
