Months after a probe returning from Mars burns up during reentry, strange creatures known as "Ancients" start appearing across Tokyo. These aggressive and dangerous beings cannot be killed with ordinary weapons. While scientists struggle to determine the cause of their sudden arrival, the monsters cause devastation around the world. Humanity finds hope in the MARS suit, a new weapon developed to defeat these enemies. However, the suit can only be worn by individuals with specific DNA. Takeru Hinata, an ordinary teenager with a troubled past, is one of the few capable of piloting this sole weapon against the Ancients. Assisted by the AAST, a special police force created to combat the dangerous creatures, the young man fights demons both personal and global while attempting to uncover the true nature of Earth's new aggressors.