There is something strange going on in the mining colony of Bowen's Landing, as one of the miners has gone missing. While expecting the arrival of her second grandchild, the miner, Lorraine Hawkes, boards the lift down into the main shaft along with a team of colleagues, only to come face-to-face with a grisly discovery, and a formidable invader who is lurking in the dark mine. Now, Lorraine has to make a crucial decision. Will she obey the company's orders, or will she make a last stand, and prevent the beast from escaping into the colony?