The year is 2031 and following the defeat of the Robotech Masters by Earth's Robotech Force headed by Dana Sterling's 15th Tactical squad, the planet faces a new threat! The spread of the Protoculture spores across vast swathes of the Earth's surface has not gone unnoticed. The mysterious alien race known as the Invid - arch enemies of the Robotech Masters - launch a full scale invasion of Earth. The remaining inhabitants of the planet must struggle to survive against the new alien threat. With only a rag-tag collection of guerilla fighters to defend them, the survivors can only pray for the return of the long forgotten Robotech Expeditionary Force (REF) to save them from total annihilation.