In many ways, hot-tempered field agent Rachel Porter deals better with endangered animals than she does with people -- which is why her superiors at the U.S. Fish and Wildlife Service dispatch her to the most god-forsaken places. Georgia's steaming coastal swampland is her latest assignment, where she quickly runs afoul of the local authorities. But someone is operating an illegal manatee water park here, and Rachel is determined to shut it down. Worse still, these fascinating mammals are dying in alarming numbers for unknown reasons. And when people being dying as well, Rachel's righteous fury is tinged with fear. Because answers and predators alike are waiting for her in a dark and terrifying place: a toxic "Dead Zone" that spells certain doom for any trespassing human, manatee ... or wildlife agent.