Deep in the Congolese rainforest, a state-of-the-art expedition team searching for ultra-rare industrial diamonds is mysteriously destroyed. The only clue is a gruesome, fragmented satellite transmission showing a blurry, man-like shape amid the carnage before the signal goes dead. Back in the United States, Karen Ross, a driven project supervisor, must assemble a new team to uncover what happened and salvage the multi-billion-dollar mission. Their one-of-a-kind advantage is Amy, a mountain gorilla trained to communicate through sign language, whose strange nightmares and drawings point to the same legendary lost city the first team was seeking.
What follows is a high-stakes race against a rival consortium, plunging the new expedition into a world of dense jungle, active volcanoes, and forgotten dangers. Equipped with cutting-edge 1970s technology, the team must confront a primal secret hidden within the ruins of Zinj, a place where human ambition collides with the raw power of nature. This journey into the heart of Africa explores the boundaries of science, communication, and survival, questioning what happens when the ancient world is disturbed by modern greed.