What disaster eradicated mankind? Was it man-made or of natural origin? One thing for certain: survival for the USS Carl Sagan and its crew will difficult at best, as while humans are no longer inhabit the Earth , they left behind deadly machines to guard the airspace against space invaders. The commander and the crew of the returning Earth ship will have to overcome those unexpected fool-proof sentries. And the machines are not the only obstacles for the travel-weary men and women of USS Carl Sagan to overcome. If they want to re-inhabit Earth.