In 2061, the tactical dolls of the major military corporation "Tekketsu Kōzō" suddenly went berserk. They turned against humanity. The special forces unit "AR Squad," tasked with suppressing the rebellion and receiving orders from the private military company "Griffin," began combat against the boss of Tekketsu, Alchemist, as the invasion intensified. Amidst the escalating battlefield, M4 and AR-15 gradually drift apart... The outcome of the battle was a brutally harsh reality.