Mining heir David Innes and inventor Abner Perry test an experimental drilling machine only to lose control of it and descend some five hundred miles beneath the Earth’s surface, where they discover Pellucidar, a vast inner world of perpetual daylight inhabited by prehistoric creatures. Captured by the ape-like Sagoths who serve the intelligent, pterosaur-like Mahars, David and Perry discover that the human inhabitants live under Mahar domination, while David meets Dian the Beautiful and struggles through dangerous misunderstandings caused by the unfamiliar customs of this strange world. Surviving captivity, monstrous creatures, and repeated conflicts, David joins forces with other humans to resist their rulers, rescue Dian, and lay the foundations for a broader struggle to free the people of Pellucidar.
