From a sinister and secret government laboratory and into the lives of certain good and evil people come two escaped creatures, one murderous and willed with rage and the other benign and compassionate. They are the end products of experiments in genetic engineering and enhanced intelligence.

When Dr. Louis Creed, the new director of student health at the local university, is first taken by a neighbor friend to the pet cemetery in the woods behind his house, he thinks it is just an eccentric, if morbid, local site.

On a six-mile hike on the Maine-New Hampshire branch of the Appalachian Trail, nine-year-old Trisha McFarland quickly tires of the constant bickering between her older brother, Pete, and her recently divorced mother.