Deep in the darkest region of the Congo, a field expedition dies mysteriously and brutally in a matter of minutes...

At the Houston-based Earth Resources Technology Services, Inc., a shocked supervisor watches a gruesome video transmission of that ill-fated team - and sees the grainy, moving image of a dark, blurred image...

In San Francisco, an extraordinary gorilla named Amy, who has a 620 "sign" vocabulary, may hold the secret to that fierce carnage. Immediately, a new expedition is sent to the Congo, descending into a world where the only way out may be through the grisliest death...