The frightful caves of the Appalachian Mountain range harbor an evil secret, and Sarah Carter (Shauna MacDonald) manages to escape with her wits barely in tact. She is covered in the blood of her missing friends. Her tale causes a police intervention squad, led by local police chief Vaines (Gavan O’Herlihy) and Officer Rios (Krysten Cummings), to force Sarah back to the ordeal she cannot remember. Police and a rescue team led by Dan (Douglas Hodge) want to return to the cave with Sarah to learn what happened to her five companions. They soon learn that an offshoot of zombies, called Crawlers, a feral group of killers now resides underground.