The story of a family struggling to survive in a world terrorized by a deadly primeval species that has evolved for millions of years in the pitch-darkness of a vast underground cave system, hunting only with their acute hearing ability. As the family seeks refuge in a remote haven where they can wait out the invasion, they start to wonder what kind of world will remain when they're ready to emerge.
When the world is under attack from terrifying creatures who hunt their human prey by sound, 16-year old Ally Andrews (Kiernan Shipka), who lost her hearing at 13, and her family seek refuge in a remote haven.