The novel is set in an alternate history in which the events of Arthur Conan Doyle's novel The Lost World actually occurred. The setting is based upon a large plateau ("El Grande" or "Tepui Grande") in Venezuela, where dinosaurs still live.
Due to the capture and exhibition of dinosaurs, movie producers such as Willis O'Brien and Ray Harryhausen never succeed, since the public's interest is instead captured by living dinosaurs. However, due to deaths caused by escaped dinosaurs and difficulty in obtaining new dinosaurs, the dinosaur circuses slowly die out.
The novel is implicitly set shortly after the Second World War.
Peter Belzoni and his father Anthony Belzoni join an expedition to return the dinosaurs belonging to the last dinosaur circus to the plateau. To reach the plateau, the expedition must deal with the vagaries of politics. One dinosaur dies en route, but the remainder are released on the plateau. However, the expedition members are trapped on the plateau and must face, and escape from, dinosaurs both real and fictional.
- Peter Belzoni, the teenage protagonist, Anthony's son.
- Anthony Belzoni, a freelance reporter and Peter's father.
- Vince Shelabarger, dinosaur trainer and unofficial leader of the expedition.
- Merian C. Cooper, Ernest Schoedsack, John Ford, Ray Harryhausen and Willis O'Brien, movie men looking for subject material on the plateau
- Lothar Gluck, the owner of the last dinosaur circus
- El Colonel (no real name given), a military man who opposes the expedition to the plateau.
Notable dinosaurs and prehistoric creatures
- Saltasaurus, a genus of sauropod dinosaur of the late Cretaceous period
- Archaeopteryx, primitive bird
- Ankylosaurus, armored dinosaur
- Centrosaurus, horned dinosaur
- Aepyornis, giant flightless bird
- Leptictidium, primitive mammal (however, the animal in the book is larger than its real-life counterpart)
- Altovenator ferox - large carnivorous theropod dinosaur
- Neostruthiomimus planensis - ornithomimisaur
- Eoavis - avisaur (based on Archaeopteryx)
- Stratoraptor velox - avisaur
- Lycognathus - therapsid
- Dog-lizard - therapsid
- Lizard-monkey - therapsid
- Lake-devil - therapsid (based on pliosaurs)
- Communisaur - a eusocial species of therapsids
- Unidentified nest-robbing mammal (loosely based on Leptictidium)
- Hammerhead Amphibian - based on Diplocaulus & Gerrothorax
- Death-eagles (fictional) - giant carnivorous birds
- Cleaner Ant
- The Lost World: the novel is set in a parallel universe where, rather than being a story, Sir Arthur Conan Doyle's "The Lost World" is an account of actual events.
- King Kong: The characters are referred to, the makers appeared, and the film is mentioned.