Maze, a large experimental base affiliated to Black Mesa in Antarctica, had discovered and extracted Xen crystal long before the disaster broke out, and successfully synthesized Xen biological DNA in the spectrometer. However, Maze managers did not report the success of the research to their superiors. It's going to be sold to the underground market. The day before the deal, a man in a blue suit attacked the ground lab. Two hours later, the ground lab lost contact with the outside world. The only security guard at Maze Underground Research Facility: Gary immediately took out the Xen Crystal analysis and destroyed it, but a large number of monsters in the prison broke through the cage and attacked the researchers. Gary had to take up arms, escape from Maze and blow it up!