Neurosurgeon Hudson Gammond lost his license to practice medicine upon his daughter's death: exploratory brain surgery. He moves to a small mountain town where he befriends the Jacoby's. Their daughter Emily has a rare form of Autism that kills its victims before they reach adolescence. Desperate, the Jacoby's will do anything to save their daughter. Hudson has an idea, one that did not fare so well for his late daughter, but this time things will be different, he's sure of it. He performs a procedure that lays down infrastructure in the brain to access intelligence, which he calls The Great Gray Superhighway. The operation is a success, Emily thrives. That is, until she begins seeing something that nobody else can see, something terrifying. It haunts her, is after her, finds a way to her through The Great Gray Superhighway.