A British couple is marooned on the coast of West Africa in the late 19th century. They build a makeshift home in the jungle, but soon perish, leaving their infant son orphaned. The child is rescued and raised by a tribe of apes. Growing up in the wild, he learns to communicate with the animals and becomes one of them. During his adolescence, he encounters a group of explorers and rescues them from danger. The leader, Major Philippe D'Arnot, is injured and taken care of by the young man, who also discovers clues about his past through the explorer's belongings.

Eventually, D'Arnot realizes the young man is the heir to the Greystoke estate in England and educates him on Western customs. With D'Arnot's guidance, he travels to England and attempts to assimilate into society, reuniting with his aristocratic grandfather and meeting new people. However, adjusting to civilized life proves challenging, as he grapples with his primal instincts and the complexities of human society. The story explores themes of identity, nature versus nurture, and the clash between civilization and the wild.