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Set in the Universal Century 0090, between Mobile Suit Gundam ZZ and before Mobile Suit Gundam: Char's Counterattack, the plot centers around Darry Neil Guns, a member of the Monotone Mouse Corporation who was repairing Texas Colony at Side 5 -a Space Colony that was damaged from the One Year War, When they are attacked by the New Summer Project terrorist organization's Colorde forces. Both the anti-Earth Federation militant group Colorde and the New Summer Project were actually being used as a front for the resurgence of the Second Neo Zeon movement under the leadership of Char Aznable. In an attempt to resist Colorde, the Monotone Mouse Corporation is forced to team up with the Earth Federation Force's Arahas force and fight. Darry Neil Guns, a fan of the Gundam, modified his worker mobile suit to resemble the original RX-78 Mobile Suit Gundam, and through mistaken identity it is acknowledged as the actual Gundam.
In F.C. 60, the 13th Gundam Fight begins. Domon Kasshu pilots the Shining Gundam as the representative of Neo Japan, the Japanese space colony. Along with his crew member Rain Mikamura, he battles the other countries' representatives in order to earn the right to rule Earth and the colonies for four years for Neo Japan. However, Domon seems to be more concerned with finding his brother and the stolen Devil Gundam.
The story focuses and revolves around the 108th Guard Squad, stationed in Aomori. A poorly equipped unit with very little military standing, it is often viewed as a 'reject camp' for pilots not making the grade for the elite units based in Hokkaido. The apparent helpless nature of this force is hardly a deterrent for the encroaching enemy armies, ever closing in on both the 108th and the rest of the empire. The young pilots of the 108th, who had dreamed on returning home, are plunged forcefully and unwillingly into a war.