Terror reigns deep beneath the streets of New York City. The subway system is plagued by a series of unsolved, bizarre and particularly gruesome murders. A young man is found in a Brooklyn station with his heart crudely ripped out of his chest. The headless body of a conductor is discovered inside the locked cab of a Number 6 train in lower Manhattan. Authorities blame these, as well as several other equally macabre crimes, on the city's growing, and increasingly aggressive homeless population. Melissa Manning, however, isn't buying that explanation. Having experienced a personal tragedy in the subway years ago, Melissa is definitely no stranger to the violence that can occur underground... but this is different. Weeks before the first murder was even committed, she's had an unsettling feeling that something horrifying was lurking within the sprawling transportation system. Many nights when traveling alone, and walking along a quiet stretch of the platform, she hears an eerie scraping sound in the distance, and has an overwhelming fear that someone - or something - is watching her. When the murders begin, and when a dark, faceless figure follows her home from the subway one night, she's convinced that this is something far more insidious and frightening than mere random acts of violence. Not only can she feel the presence of an evil entity...she knows it's just a matter of time before it comes after her.