In a dark and nasty textile factory close to a cemetery and infested of rats, many workers are missing. When the corrupt manager Warwick is forced by a sanitary agent to hire the exterminator Tucker Cleveland, he asks Tucker to use less poison than necessary to reduce the costs. Meanwhile, the drifter John Hall applies for a job and accepts the position of operator of a textile machine in the graveyard shift. What they do not know is that there is a huge creature is in the underground of the mill threatening the workers.