Named "Juggernaut," these are the unmanned combat drones developed by the Republic of San Magnolia in response to the attacks from the autonomous unmanned drones of the neighboring Empire Giad, known as the "Legion." But they are only unmanned in name. In reality, they are piloted by those in the group known as the Eighty-sixers—those considered to be less than human and treated as mere tools. Determined to achieve his own mysterious goals, Shin, the captain of the Spearhead squadron, which is made up of Eighty-sixers, continues to fight in a hopeless war on a battlefield where only death awaits him.