Doom 3: Worlds on Fire (Doom 3)

Special Ops Marine Lieutenant John Kane was once a careerist simply glad to have a job, and couldn't care less about politics just as long as Uncle Sam's check cleared. But that was before he listened to his conscience and disobeyed a direct order. Busted down to private, Kane has been reassigned to the "U.S. Space Marines" -- the private army of the UAC -- with the prospect of becoming little more than a glorified security guard on Mars....

Now Lt. Kane's fate leads him to Mars City -- part environmental community, part lab center, and all owned and protected by the UAC. It's a strange world with a fatal environment, and the thousands who live and work within the city have already begun to think of themselves as Martians. And away from Mars City, at the strange ancient sites uncovered on the planet, a small squad of marines stand guard while scientists uncover wall glyphs and search for artifacts, having already found something that is so far amazing and inexplicable -- including the relic called "U1," nicknamed "the Soul Cube" -- and unknown to all, the bringer of destructive chaos and unspeakable horror....