The Trellixian Empire was constantly expanding, seeking new worlds for their ever-increasing population. If worlds were discovered with existing sentient populations, they were cleansed to make room for colonization. Hundreds of budding civilizations had been eliminated by Trellixian battle fleets.
On Earth years in the past, a scout ship fleeing from the Trellixians crashed. Scientists investigating the wreckage discovered what the Trellixians had done to the world the scout ship escaped from. They also discovered it was only a matter of time before the Trellixians reached Earth.
A daring plan was implemented involving the major world powers. They would prepare in secret for the coming of the alien invaders. The only question was, how could one world resist a galactic empire?