2517AD. The human species is threatened by an aggressive sentient alien race known as the Ryzin. Desperate for a new home after stripping their own of resources, out of fuel, out of food, and with no other hospitable planets in range, the Ryzin have settled near Earth as the best hope for their kind. The humans have no intention of giving up their ancestral homeworld. Ships scramble from bases on Luna and from the Ryzin mothership. This interstellar war of attrition will determine the fate of Human and Ryzin alike.