Following the alleged death of its 99th emperor, the Holy Britannian Empire collapsed, allowing the territories it controlled to finally reclaim their independence. While the majority joined the United Federation of Nations, an organization dedicated to establishing permanent peace, remnants of the tyrannical empire persist. One such faction, Neo-Britannia, has seized control of Japan's Hokkaido island after assassinating its governor, Juugo Sumeragi. The Seven Shining Stars, a resistance movement in Hokkaido, faces a deadlock as it attempts to determine how to defeat the Neo-Britannian Empire. As a final measure, it recruits the Nameless Mercenaries: brothers Rozé, a brilliant strategist, and Ash, an outstanding Knightmare pilot. Although Rozé and Ash are of Britannian descent, they have earned a reputation by safeguarding the Japanese and eliminating imperial officials. With their assistance, the resistance might finally succeed in retaking its territory and averting another era of terror.