After a dinner with friends, psychologist Phil Stanton and his wife Cathy are followed by a white pickup truck. Phil thinks he loses their pursuer, but when they reach their remote home the pickup truck is right behind them again. Megan, Phil and Cathy's fourteen-year-old daughter, steps onto the front porch to see what's happening. Phil tells Megan to go back inside, and as he calls the police the truck turns around and leaves. The police arrive, but there isn't much they can do because Phil doesn't have the truck's license plate number or a description of the driver.
The stalker knows where Phil, Cathy, and Megan live now, and over the next few days the terror escalates: Phil treats a mysterious patient with violent tendencies who issues a threatening warning; Phil is haunted by nightmares, and Cathy hears him murmuring strange things in his sleep; soon Cathy discovers clues that lead her to believe that Phil may know who their stalker is and why he has chosen them. Dark things are beginning to turn up from Phil's past . . .