On January 1, 1778, mankind abandons the earth and flees. More than a billion humans remain on the surface of the earth, still fighting against the alien invaders. The cadets are reassigned to the "alter native" class, which means that they are no longer cadets. They were never told about alternative iv, which was to evacuate the Earth, and they were divided between those who were permitted to board the alien fleet and those who remained on the ground.