Scientist Karen Ross (Laura Linney) is sent by her father-in-law, mogul R.B. Travis (Joe Don Baker), to the Congo to determine the whereabouts of his son's missing diamond-hunting team. Led by expert guide Kelly (Ernie Hudson), Ross and a mismatched search party -- including primatologist Dr. Peter Elliot (Dylan Walsh), treasure hunter Herkermer Homolka (Tim Curry) and a gorilla -- discover a danger far more sinister than anything they expected to find, even in the heart of the jungle.