When a severely wounded young woman is brought in to the emergency room, Sara Linton finds herself drawn back into a world of violence and terror. The woman has been hit by a car but, naked and brutalised, it's clear that she has been the prey of a twisted mind. When Special Agent Will Trent of the Criminal Investigation Team returns to the scene of the accident, he stumbles on a torture chamber buried deep beneath the earth. And this hidden house of horror reveals a ghastly truth-- Sara's patient is just the first victim of a sick, sadistic killer.