Challenger is trying to harness the energy of lightning when a gigantic bolt splits the sky. In a blinding flash, the ground is scorched, and by some miracle, no one is injured. In the silence after the thunder, the sputtering sound of a small engine is heard, and a small plane appears in the distant sky. It drops from view, crashing into the jungle. All survive: four modern day tourists - a couple, a middle-aged man and a gorgeous young woman. The group are set upon by a hostile tribe and taken prisoner. Our explorers arrive to find only the disabled plane, which Challenger and Malone set about trying to repair. Kenner, the leader of the hostile tribe, is fascinated by his captives but keeps them in a dungeon. Roxton and Veronica devise a plan to save them.