Deep beneath the city streets lurks a creature hideous beyond description, powerful beyond imagining, a creature so dangerous that it can destroy its victims by the virulence of its thoughts. The emanations of its computer-like brain invade every sanctuary, searching for those it would destroy. It is remorseless, cunning and inhuman. The pitiful human weaklings it has chosen as prey shudder with terror and disgust, but there is no escape . . .