During the May Day holiday, Lu Yanqiu, the office director of the mining company, and three friends entered the company's old mining plant that had been abandoned for 20 years. There are trapped souls who refuse to leave, and there are also hidden secrets that the living do not want to be discovered. They were unable to get out at first, and then found that their every move was captured by the camera and passed to the person who swallowed the factory. In seven days, from fear to anger, they not only encountered a buried history, but also became witnesses to the corruption case that had been delayed for 20 years.
