While Roxton goes hunting, Malone and Agnes are attacked by the allosaur from the night before, but manage to evade it when it falls into a manmade trap. The next morning, Malone discovers a lake that he names after his fiancé Gladys and has a brief encounter with an apelike creature he describes as looking almost human.

Venturing deeper into the plateau's jungle, they discover several species of dinosaur, including a flock of pterosaurs which injure Summerlee and an allosaur that attacks their campsite that night. However, when all but Kerr make it across, he suddenly knocks the tree into the gorge and leaves Challenger and the others stranded there, claiming that it belongs to the Devil. They later find a gorge leading straight to the plateau and use a tree as a substitute bridge to reach it. They reach the edge of the plateau and find a cave concealing a pathway but find a blockage. However, in the jungle, the expedition's porters flee out of superstition, but Kerr arrives and tries to convince Challenger to turn back. Agnes volunteers to join the expedition as a translator. Roxton takes a liking to Agnes and flirts with her. They travel to a Christian mission in the Amazon, meeting Agnes Cluny and her uncle Reverend Theo Kerr, who condemns Charles Darwin's theory of evolution. On the voyage to South America, Challenger reveals a map created by a Portuguese man named Father Luiz Mendoz leading to a Brazilian plateau where he encountered dinosaurs during a previous expedition. However, hunter Lord John Roxton and Daily Gazette columnist Edward Malone both volunteer to join the expedition. Challenger proposes an expedition to discover the home of the pterosaur, but is dismissed by the science community. Returning to England, he crashes a lecture held at the Natural History Museum by his colleague Professor Leo Summerlee. While in the Amazon rainforest, Professor George Challenger shoots an animal he believes to be a pterosaur.

Watch return to the lost world 1992