A kid inherits his dead father's super robot and finds out the entire city he grew up in was his father's blueprint for survival. The robot itself isn't the inheritance, the responsibility is. Daigo has to choose between the life his sister kept running and the life his father designed him to live, and the Gordian forces that choice every single episode. This is mecha that understands that the real weight isn't in the cockpit. It's in knowing someone else's dream is now yours to either complete or burn down.

The Earth has turned into a desert wasteland, and those who survived are working to rebuild their communities. Daigo Otaki is an orphan brought up by his uncle. As an adult, he learns that Victor City was planned by his father, a brilliant scientist, and that his sister Saori has been running it. Saori urges Daigo to accept what their father left him: Gordian, a super robot system. Daigo joins the Mechacon 18th Regiment, a law enforcement unit that defends Victor City from attacks by the Madokuta organization. Part mecha action and part science fiction mystery, the story slowly reveals who Daigo really is, who the invaders are and what they are after, and what Gordian is.