The earth had turned into a barren desert after the survivors worked to rebuild communities. daigo otaki was raised by his uncle as an orphan and grew up to discover that his father, a brilliant scientist, planned victor city. his sister saori managed it. she urged daigo to inherit the super robot system gordian, left behind by their father. daigo joined the mechacon mechanic combat 18th regiment unit, which defended victor city against attacks from madokuta.