The story follows the adventures of a group of people who set out on an expedition to find the lost city of Kor. The protagonist of the novel is Alan Vernon, a young Englishman who inherits a large fortune from his uncle. Alan is fascinated by the stories of Kor, a city that is said to have been built by a powerful civilization that existed thousands of years ago. He joins an expedition led by a man named Ignacio, who claims to know the location of the lost city. As they journey deeper into the African wilderness, the group faces numerous obstacles and dangers, including hostile tribes, wild animals, and treacherous terrain. They also encounter a mysterious woman named Rodericka, who has her own reasons for wanting to find Kor.