While investigating the scene of a gruesome mass murder, Detective Sebastian Castellanos and his partners encounter a menacing and powerful force. After witnessing the slaughter of fellow officers, Sebastian is ambushed and knocked unconscious. When he awakens, he finds himself in a deranged world where hideous creatures wander among the dead. Facing unimaginable terror, and fighting for survival, Sebastian embarks on a daunting journey to unravel that which is behind this evil force.