The animals are acting strange around Everglades City, Florida. So strange that Dr. Beverly Kanter, a Harvard toxicologist, arrives to reassure the residents that the behavior is only caused by the run-off water from the nearby citrus grove. She befriends Preston McPherson, the local lawyer/activist, and Matthew, his 12-year-old son. When their houseboy, George, is killed by enraged manatees, Matthew is stranded with Dolly, a deformed adult Thalidomide child from the 1960s who lives alone in the swamps. Beverly and Preston set out to rescue him, secretly tailed by Matthew's girlfriend Nicole, and encounter wild boars and vicious deer. Dolly's makeshift house burns down, and she and Matthew head for the distant highway, where they discover two men illegally dumping estrogen-mimicking pesticides into Panther Lake. This chemical sludge is the real culprit: Beverly surmises the panthers have become hyper-virile due to over saturation of their estrogen receptors, which has resulted in a paradoxical androgen overload. The two men are attacked by enraged alligators; Matthew and Dolly narrowly escape with Beverly, Preston, and Nicole. When angry panthers attack, Dolly sacrifices herself to save the others. The survivors learn the real effects of man-made chemicals on nature.