During a communion service at a village church, the teenage son of a vicar brutally attacks his father with an axe. The horrified congregation watch the son escape and during a frantic police search rumours arise that the boy was involved in devil worship. Professor Matt Hunter, an atheist ex-minister and expert on religion, is brought in to advise, yet he quickly suspects the church attack may have a far more complex cause.
Meanwhile, a ten-year-old boy called Ever grows up in a small Christian cult. The group believe they are the only true humans left and that the world is filled with demons called Hollows, but they're working on a bizarre ritual that will bring peace and paradise to the world. Soon, the worlds of Matt and Ever will collide in one awful, terrifying night where Matt is thrown into the frightening and murderous world of religious mania.