In the Congo, Charles Travis (Bruce Campbell) is testing a communication system by laser with his former fiancee Dr. Karen Ross (Laura Linney) for the TraviCom network. Charles is the son of the millionaire R.B. Travis (Joe Don Baker), who owns the TraviCom and is Karen's employer. Charles and his friend Jeffrey Weems (Taylor Nichols) find the ruins of a lost city, but are somehow killed. Meanwhile, their camp is completely destroyed and then the camera is shut down by a creature. Travis discloses to Karen that his son was actually trying to find a rare blue diamond in the Congo and sends her to look for him. Meanwhile, Dr. Peter Elliot (Dylan Walsh) and his assistant Richard (Grant Heslov) are testing communication with the gorilla Amy (Misty Rosas), and they decide to take her back to the Congo, since the animal seems to miss her birthplace. However, they have funding issues, but Romanian philanthropist Herkermer Homolka (Tim Curry) offers to financially assist them. In the airport, Karen provides more money and joins the expedition. In the politically unstable Africa, they meet experienced guide Captain Munroe Kelly (Ernie Hudson), who bribes Captain Wanta (Delroy Lindo), to let them go. Further, he discloses that Homolka's real intention is to find the Lost City of Zinj. Then they embark in a plane in the beginning of a dangerous adventure in the Congo.