Nine years ago, the Empire of Giad declared war on all neighboring countries using an army of autonomous drones known as the Legion. Threatened by the soulless killing machines, the Republic of San Magnolia, home to the silver-haired Alba race, evacuated its citizens inside 85 districts and developed supposedly unmanned drones known as Juggernauts to counter the Legion. Even after years of war, the Republic boasts that they have suffered zero casualties. However, the battlefield bathed in crimson recites a different melody.

The hand dealt to the Colorata people—a minority forced into living in the "nonexistent" 86th district—is one of utter contempt and scorn. Looked upon as human filth, they are ordered to pilot the Juggernauts as Processors under the command of Republican Handlers.

Vladilena Milizé, a republican soldier with a strong sense of justice, detests the way her countrymen treat the 86. When she is assigned to the Spearhead Squadron as their handler, she meets a group of oddballs and eventually grows attached to them—particularly their captain, Shinei Nouzen, a boy with a pure sense of purpose and resolve. However, the path they walk is one riddled with death, and growing close to an 86 may have just set Vladilena down a path of despair.