It was a map made by Cody, one of Master Chief's friends. Both Chief and Cody referred to it as a "beast" map. However, Arbiter thought that it was poor, as the walls were very poorly aligned. The map had a docking bay that went outside, which had a Falcon on the landing pad..
The map was designed for Infection, which was what Chief, Arbiter, Cody, Brent, and other players were playing. All the players except Chief, Arbiter and Cody were zombies. They were aiming to get to the falcon.