A massive asteroid named Vulcan's Hammer is detected to be on a collision course with Earth, and all attempts to divert it from this path have failed. The last attempt, firing a large nuclear warhead at the asteroid, actually ended up splitting it not into five chunks (which would have averted disaster) as humanity hoped, but rather two asteroids. Now, instead of destroying the earth, it will simply wipe out nearly all life on Earth's surface. Extinction is not an option, and so a mission is organized to create a colony on a world elsewhere in the galaxy as the last hope for mankind's survival. The player is in charge of that mission.