The series takes place concurrently with Mobile Suit Gundam, during the One Year War. In U.C. 0079, the Earth Federation’s Moore Brotherhood and the Principality of Zeon’s Living Dead Division engage in a fierce battle in the “Thunderbolt Sector” (サンダーボルト宙域, Sandāboruto Chū-iki), a shoal zone littered with debris from destroyed space colonies, named for its frequent electrical discharges. Since the outbreak of the war, Zeon forces have secured the Thunderbolt Sector as it is a vital supply route to the Zeon-aligned A Baoa Qu asteroid fortress. The story focuses on Federation soldier Io Fleming as he battles Zeon’s best sniper, Daryl Lorenz.