After Garuma died and Char disappeared, in the aftermath in North America――. Universal Century 0079. Nanao, a soldier belonging to the Earth Federation Forces, was searching for the whereabouts of his new squad leader who went missing before reporting for duty. His name is "Leo Barnack." Having crash-landed in Zeon-controlled territory, where on earth did he go――. Nanao and his squad members risked danger to track their new leader, but they encountered Zeon forces and were pushed into a desperate, dire situation. However, the one who appeared there was――!? An authentic One Year War military story begins!!