Asagi Briggs is a 15-year-old civilian with multicolored hair and a no-nonsense personality, traveling aboard the civilian transport ship Prospero during the Gryps War's final days. Accompanied by animal mascot dolls and her younger sibling Takuya Briggs, her journey to Earth is disrupted when the Prospero becomes caught in a battle between the Titans and AEUG factions. Faced with this crisis, Asagi and Takuya must pilot an Aerial D300 lifeboat through atmospheric re-entry amid ongoing combat, their survival depending on navigating the vessel safely.

Unexpected assistance arrives when a custom-painted Zeta Gundam intervenes to aid the Prospero. Its pilot—unidentified but bearing a voice resembling renowned One Year War ace Amuro Ray—provides crucial support. With the Zeta Gundam's aid, Asagi and Takuya successfully guide the lifeboat through atmospheric re-entry. The events frame a civilian perspective within the larger conflict, emphasizing survival over direct combat.