Journalist Catherine comes to the Devonshire coast, famous for its beaches and natural beauty. But when prehistoric artifacts and a huge number of human remains are discovered in Brickbear, a nearby town, Catherine's life changes forever. Helen lost her brother 6 years ago. Shortly before his disappearance, he recorded strange sounds that were heard from underground near the Brickbury Caves, and this recording leads Helen to a place where people killed each other in the primitive era, and on the walls there are still images of their nameless gods. There are rumors of the appearance of a mythical red people here, and the curious have been disappearing for many years. Guests are not welcome here, and local residents believe that an ominous force still lurks underground, which only the most desperate can fight, because little can resist the crimson tide of primitive cruelty.