Their peace was a fragile one, however. Fifteen years later, high school student Inaho Kaizuka witnesses the plotted assassination of the Vers Empire's Princess Asseylum Vers Allusia, who had come to Earth in hopes of repairing the relationship between the empire and its homeland. The ceasefire is shattered, and the Martians declare war on the Terrans once again. In the face of this insurmountable enemy, Inaho and his friends must now fight against the Vers Empire to settle the war once and for all.