There was once a great conflict known as the "Calamity War." Roughly 300 years have passed since the end of this war.

The Earth Sphere had lost its previous governing structure, and a new world was created under new systems of government. While a temporary peace had arrived, the seeds of a new conflict were being sown in the Mars Sphere, far away from Earth.

Our hero, a boy named Mikazuki Augus, belongs to a private security company called Chryse Guard Security (CGS). The company accepts a mission to escort Kudelia Aina Bernstein, a girl who seeks to liberate the Martian city of Chryse from the rule of one of Earth's major powers. However, the military organization Gjallarhorn attacks CGS in order to nip this rebellion in the bud. CGS begins an evacuation, using Mikazuki and the other children as decoys.

Orga Itsuka, the leader of the boys, decides to take this opportunity to rise up in revolt and launch a coup d'état against the adults who have been oppressing them. He gives Mikazuki the task of repulsing Gjallarhorn, and Mikazuki enters battle using the Gundam Barbatos, a mobile suit from the Calamity War era which has been serving as CGS's power source.


Mikazuki Augus is part of Tekkadan, an organization that jumped to fame from the battles involving the escorting of Kudelia Aina Bernstein to Earth and the Arbrau primary elections. The conflict exposed the corruption of Gjallarhorn as well, and the world was changing slowly but surely.

Tekkadan, with the rights to halfmetal as negotiated with Arbrau, became a direct affiliate of Teiwaz. That resulted in abundant funds and more people interested in joining, growing massively to even have a branch on Earth.
Kudelia, learning about the world from her journey to Earth, founded Admoss Company to strive for the financial independence of Mars both in reality and in practice. However, there are many who do not look favorably about the rise of the youngsters who are trying to start something new.

Admoss Company will be inspecting a mining site of halfmetal, and hired Tekkadan to guard them. There, the leader of Tekkadan, Orga Itsuka, senses an attack from a new enemy. Under Orga’s command, Tekkadan, including Mikazuki in the mobile suit Gundam Barbatos Lupus, head out to repel the enemy.