They never took the Dork threat too seriously. First they thought they wouldn't dare attack, then they thought we'd defeat them easily... mankind never learns from it. Now the Earth is overrun by these infectious creatures, and you're the pilot tasked with saving it. Doesn't that sound familiar from one of the combat simulators you trained on? 

Here's how things stand. You're at the controls of your old ship, in a secret hangar, preparing to try to escape from Earth, travel across five planets to collect the parts for the Genesis, assemble it and finally return home, to free your planet alone from an invasion of angry aliens.