In the year A.C. 196, after the war between Earth and its neighboring space colonies ended and the Earth Sphere Unified Nation was formed, four of the five Gundam pilots opt to disarm and jettison their mobile suits into the sun, following the trend of unity and prosperity among mankind. However, their plan is abruptly shelved when a rebellion led by Mariemaia Khushrenada, who claims to be the child of late dictator Treize and aims to rule the world on his behalf, breaks out unexpectedly. Realizing that they are the last line of defense for the Earth Sphere, Heero Yuy, Trowa Barton, Duo Maxwell, and Quatre Raberba Winner hurry to recover their Gundams and defend the hard-earned peace of the colonists. But their mission will not be easy, especially when their former comrade Wufei Chang has joined forces with Mariemaia's cause. Though the pilots are determined to carry out their final duty, victory will require a fierce battle.