During the 1972 Apollo 17 mission to the moon, humanity discovered a strange hypergate leading to Mars. Upon entering, the astronauts found ancient technology called "Aldnoah," which soon triggered mass migration to the planet and the establishment of the Vers Empire to rule Mars. Descendants of this new civilization grew to resent Earthlings for their abundant resources. This resentment led to a declaration of war, ending with the hypergate's destruction in the infamous "Heavens Fall." The consequences were catastrophic: the Moon was obliterated, and Earth suffered irreparable damage from multiple meteor impacts, earthquakes, and tsunamis. Fifteen years later, a ceasefire has established a fragile peace. Princess Asseylum Vers Allusia arrives on Earth to promote lasting friendship between the two races. However, not everyone is satisfied with the abrupt end of the first battle; certain forces have been waiting for this moment to ignite the spark of a new war. When terrorists attempt to assassinate the young princess, Martian soldiers retaliate by launching an assault, descending from space ready to enslave Earth's inhabitants once and for all.