When 22-year-old Alison Mannering returns to her home in northeastern Pennsylvania after college, she finds a troubling situation. Her father, Guy Mannering, a longtime coal miner, has died recently under suspicious circumstances, and her mother refuses to provide any details of his passing. Alison feels she has no option but to investigate the matter herself, enlisting her high school sweetheart, Randy Kroeber, as well as Randy's twin sister, Andrea called Andy, to assist her. In the process, Alison and her cohorts become enmeshed in an inconceivable horror that goes back a century or more and is somehow involved with the coal mine, now controlled by the remote and enigmatic Conrad Brashear. Beyond the possibility of danger or death to herself and her friends, Alison comes to realise that what is lurking in and below the mine poses a mortal threat to the safety of the planet.