Deep in the African rain forest， near the legendary ruins of the Lost City of Zinj， an expedition of eight American geologists is mysteriously and brutally killed in a matter of minutes. Ten thousand miles away， Karen Ross， the Congo Project Supervisor， watches a gruesome video transmission of the aftermath: a camp destroyed， tents crushed and torn， equipment scattered in the mud alongside dead bodies -- all motionless except for one moving image -- a grainy， dark， man-shaped blur. In San Francisco， primatologist Peter Elliot works with Amy， a gorilla with an extraordinary vocabulary of 620 "signs，" the most ever learned by a primate， and she likes to fingerpaint. But recently， her behavior has been erratic and her drawings match， with stunning accuracy， the brittle pages of a Portuguese print dating back to 1642 . . . a drawing of an ancient lost city. A new expedition -- along with Amy -- is sent into the Congo where they enter a secret world， and the only way out may be through a horrifying death . . .