At the start of the 21st century, Japan plunges into a state of financial and political decline. In an attempt to revitalize their nation, the army develops the next generation of battlefield weapons in the form of tactical suits known as Tactical Armor (TA). Despite giving a significant advantage in mobility, TAs place a heavy strain on their pilots, and few people are capable of handling them. Yuushirou Gouwa is one such talented pilot who is unusually adept at steering these new machines. As the fourth son of the esteemed Gouwa family, Yuushirou is no stranger to the influence of powerful authority. His abilities and knowledge of the TAs are soon tested, as other geopolitical entities are also attempting to develop their own combat-ready versions. Things take a dire turn when Yuushirou encounters a mysterious girl, who cautions him of the future that awaits them should he revive a "terror." While he tries to heed the warning, Yuushirou's family may be more involved in the rising conflict than they let on.