On December 25, 2003, an upscale Filipino family gathers at a remote place in the Sagada Mountains for a Christmas Day reunion dinner. It's a happy occasion where the main character, Susan, announces her marriage engagement to her boyfriend, Ken, whom she brought with her. Suddenly, the group is cut off from civilization and plunged into darkness by forces that defy natural laws and shut down all types of modern technology. One by one, the family members die or disappear in weird and horrific ways. The few who are left, including Susan, struggle for survival and against family conflicts and demonic forces, to find out what's "out there" and what is happening. Finally, Susan and the few left alive must understand the cult writings in an old book, to prevail against demonic forces that threaten to consume them all. They have to understand and overcome a dark, pagan religion and the need for exorcism, as well as family secrets, in order to survive. The alternative is life in a hellish "heaven" more terrifying than death.