The book Congo is about a group of people who go to the African Congo to return a gorilla to her homeland and to find type IIb blue diamonds. On their journey, they discover the lost city of Zinj and a new species of killer gorillas, which they must overcome to survive.
The story takes place in June of 1979. The three main characters are Dr. Karen Ross, supervisor of Earth Resources Technology Services (ERTS), Dr. Peter Elliot, a primatologist who trained a gorilla named Amy to speak by the use of sign language, and Charles Munro, the guide who leads the expedition through the Congo. ERTS has already sent an expedition of eight into the Congo to retrieve type IIb blue diamonds.
They are contacting them back at the base in Houston. The camera in the expedition’s camp turns on revealing a destroyed campsite: torn tents, supplies and clothing scattered everywhere, and dead bodies. As the camera moves around scanning the area a big gray object runs by the camera and destroys it. Every at ERTS is in shock. They replay the footage and freeze it on the big gray object. It looks like a gray gorilla, but gorillas don’t kill people.
Karen Ross decides to take another expedition into the Congo to get the blue diamonds. Because of the bewilderment over this incident, she contacts Dr. Elliot to find out what this gorilla is. She tells him that they’re going to the Congo and he wants to come and bring Amy, his gorilla. Amy has been experiencing bad dreams because of her past which is unknown to Dr. Ross. She begins finger painting which helps her sleep at ease because tries to banish the dreams onto paper.
Elliot realizes she wants to go to the jungle because all her paintings are of it. The expedition leaves quickly because there is a competing company that is also making its way to the Congo to get the blue diamonds, which are an amazing source of energy. The expedition is set to meet Charles Munro, the best guide there is, to guide them through the Congo.
They discussed business matters and quickly headed to Nairobi. From Nairobi, they took their final plane to go to the Congo. At that time a civil war had started in Africa and both sides were shooting everything, including the expedition’s plane. Everyone had to take a parachute and jump out of the plane. This was a major delay in the time the expedition had to beat the competition to the diamond site. The expedition: Ross, Elliot, Munro, Amy, and some African men; have to walk the rest of the way to the diamond site.
On their way, they encounter many dangers like cannibalistic tribes, angry hippos, crocodiles, and a volcano ready to burst. As they are walking through the jungle Ross is informed on her computer that the competition has already reached the site and there is no point to continue. Later on, they find the competition’s campsite destroyed and all the people are dead.
During their journey, they have an encounter with mountain gorillas. Amy runs off with them because she thinks the group is mad at her. After all the troubles and danger they finally arrive at a place to make camp, which turns out to be the lost city of Zinj which contains the blue diamonds.
They are very excited to have made such a great archeological discovery and go exploring the city for the rest of the day. At night they set up an electric fence, sensor guns, and sensor lasers. This is their first encounter with the gray killer gorillas. The gorillas showed signs of intelligence by attacking different parts of the electric fence to get in, they also wheezed to one another and used hand signals, which served as a language.
The next day while studying paintings in one of the houses of the city they discovered the story behind the city. The city has diamond mines under it and they trained gorillas to be like watchdogs to guard the mines. These “watchdogs” turned on their masters and these killer apes rule the city. The team dug a moat around the camp because it is known that no gorilla will cross even the smallest body of water.
That night the gorillas came and the same wheezing noises were heard used a tree trunk as a bridge over the moat and some of them made a distraction while others used a stick to lift open the fence and kill some of the African people. Later the team studied the body of one of the dead animals. It was a little smaller than a gorilla and weighed less and its fur color was gray.
The next night the same thing happened: more gorillas slipped in unnoticed, killed some of the African people, and made a clean exit. The next day Amy returned to the campsite and told Elliot that these gray gorillas are bad creatures and that she could understand them a little. Elliot thought of a plan, he and Amy went to the lair of these gorillas and focused on one. Amy would explain to Elliot what each noise meant.
By the end of the day they had down the meaning of a few words. Elliot made a tape with the words: GO AWAY, NO COME, and BAD HERE. As the gorillas attacked that night he played the message and they all left. The plan had worked. The next day the volcano was ready to blow which meant they had to leave quickly. On their way a cannibal tribe attacked them. They managed to escape in a hot air balloon and Amy was set free and lived with a gorilla troop. Ross got her blue diamonds and went home happy.