Michele Marshall, a young professor, witnesses a brutal slaying in downtown Washington, D.C. The murderer gets away, and hours later she hears an intruder in her nearby home. Her life is threatened. Someone she doesn't see gets uncannily near her. She and Jorge Sanchez, her partner, become victims of a campaign of harassment and vandalism that is unbelievable even by the standards of their crime-ridden neighborhood. The police can't help them since the culprit is never seen and leaves no credible evidence. Fearing for Michele's life, Jorge is determined to find their elusive adversary. The former Marine is trained to hunt down people who don't want to be found. But hunting down a person he can't prove exists requires more than the Corps ever taught him.