You play as a marine recruited upon the UAC's [Union Aerospace Corporation] research facility on Mars. Known for their top field in science, the UAC are able to conduct research into several scientific areas, including advanced weapons development, biological research, space exploration and teleportation. Due to the facility's position on Mars, the UAC can perform its operations outside of legal and moral boundaries. But the employees on the base are unsettled due to a large amount of incidents involving hearing voices, unexplained sightings and increasing cases of paranoia and insanity. After settling in, you must then investiage the Delta Labs to find a scienist who has been missing. But once you find him, all hell breaks loose.