In the year Post Disaster 323, over three centuries have passed since the devastating “Calamity War” between Earth and Mars. Mars has been successfully transformed into a habitable planet and colonized by humans. Despite significant technological progress, the inhabitants of Mars yearn for liberation from Earth’s control and strive to enhance their quality of life. Although many Martian nations have gained some degree of autonomy, the planet remains heavily reliant on Earth for economic growth. Mikazuki Augus, a young orphan, is part of a group of children employed by Chryse Guard Security, a civilian security firm tasked with protecting the Martian Princess Kudelia Aina Bernstein. She is determined to secure independence for her nation, Chryse, from Earth’s dominance. One day, the group is ambushed by Gjallarhorn, an Earth military organization intent on quashing the Martian independence movement. In the midst of the attack, Orga Itsuka, the leader of the children and the Third Army Division within CGS, chooses to defy the adults and superiors who abandoned the children and soldiers to serve as decoys. Augus is now faced with a decision: to stand by his friends or fulfill his mission, as he encounters the legendary mobile suit, the Gundam Barbatos.