In A.G. 101, the Angel space colony suffers a devastating attack by an unknown enemy called "UE", leading to widespread destruction and marking the infamous "Day the Angel Fell". This event initiates humanity's fight for survival, and the story begins in A.G. 108 with the UE's assault on the Ovan space colony, where Flit Asuno takes refuge after escaping Angel's demolition. When UE kills Flit's mother, she entrusts him with an object known as the "AGE Device", containing the plans for the powerful Gundam weapon, also referred to as the "Messiah".
Using the blueprint, Flit devotes years to studying engineering on Earth Federation's Nora space colony and designing the Gundam AGE-1. In A.G. 115, just as the UE attacks Nora, Flit completes the Gundam and joins the battle to rescue the colony's inhabitants. After losing his home twice to the UE, Flit vows to fight them directly and volunteers to pilot the Gundam for the Diva mobile suit squad. With the help of their allies, Diva and her crew achieve a decisive victory by destroying the UE's hidden fortress on the Ambat asteroid. There, they discover that UE is actually descended from a failed human mission abandoned on Mars by Earth Federation. These descendants now form their own nation, Veigan, and pose a formidable threat to humanity.
